diff --git a/packages/discovery-index/scripts/validate-posthog-release.mjs b/packages/discovery-index/scripts/validate-posthog-release.mjs
index 89df6c1046..5534a4eed5 100644
--- a/packages/discovery-index/scripts/validate-posthog-release.mjs
+++ b/packages/discovery-index/scripts/validate-posthog-release.mjs
@@ -26,6 +26,19 @@ function apiBaseUrl(value) {
   return (nonBlank(value) ?? DEFAULT_POSTHOG_APP_HOST).replace(/\/+$/, "");
 }
 
+// GET .../error_tracking/symbol_sets returns each symbol set's `release` as a NESTED OBJECT
+// ({id, hash_id, created_at, metadata, version, project}, per PostHog's own
+// ErrorTrackingRelease/ErrorTrackingSymbolSet dataclasses) -- never a flat string. Reconstructing
+// "{project}@{version}" here is what actually makes this comparable to our own POSTHOG_RELEASE
+// convention (the same "{release-name}@{release-version}" split posthog-cli's --release-name/
+// --release-version flags combine server-side into the release posthog-cli itself resolves).
+function releaseIdentifier(release) {
+  if (!release || typeof release !== "object") return undefined;
+  const project = nonBlank(release.project);
+  const version = nonBlank(release.version);
+  return project && version ? `${project}@${version}` : undefined;
+}
+
 export function loadPostHogReleaseValidationConfig(env = process.env) {
   return {
     // The same personal API key posthog-cli's upload step uses (error-tracking write + organization read
@@ -89,7 +102,7 @@ export async function validatePostHogRelease(env = process.env, fetchImpl = glob
   requireConfig(config);
 
   const symbolSets = await fetchSymbolSets(config, fetchImpl);
-  const forRelease = symbolSets.filter((set) => nonBlank(set?.release) === config.release);
+  const forRelease = symbolSets.filter((set) => releaseIdentifier(set?.release) === config.release);
 
   const failures = [];
   if (forRelease.length === 0) {
diff --git a/review-enrichment/scripts/validate-posthog-release.mjs b/review-enrichment/scripts/validate-posthog-release.mjs
index 9d2a0deb07..1d63f823ba 100644
--- a/review-enrichment/scripts/validate-posthog-release.mjs
+++ b/review-enrichment/scripts/validate-posthog-release.mjs
@@ -25,6 +25,19 @@ function apiBaseUrl(value) {
   return (nonBlank(value) ?? DEFAULT_POSTHOG_APP_HOST).replace(/\/+$/, "");
 }
 
+// GET .../error_tracking/symbol_sets returns each symbol set's `release` as a NESTED OBJECT
+// ({id, hash_id, created_at, metadata, version, project}, per PostHog's own
+// ErrorTrackingRelease/ErrorTrackingSymbolSet dataclasses) -- never a flat string. Reconstructing
+// "{project}@{version}" here is what actually makes this comparable to our own POSTHOG_RELEASE
+// convention (the same "{release-name}@{release-version}" split posthog-cli's --release-name/
+// --release-version flags combine server-side into the release posthog-cli itself resolves).
+function releaseIdentifier(release) {
+  if (!release || typeof release !== "object") return undefined;
+  const project = nonBlank(release.project);
+  const version = nonBlank(release.version);
+  return project && version ? `${project}@${version}` : undefined;
+}
+
 export function loadPostHogReleaseValidationConfig(env = process.env) {
   return {
     // The same personal API key posthog-cli's upload step uses (error-tracking write + organization read
@@ -88,7 +101,7 @@ export async function validatePostHogRelease(env = process.env, fetchImpl = glob
   requireConfig(config);
 
   const symbolSets = await fetchSymbolSets(config, fetchImpl);
-  const forRelease = symbolSets.filter((set) => nonBlank(set?.release) === config.release);
+  const forRelease = symbolSets.filter((set) => releaseIdentifier(set?.release) === config.release);
 
   const failures = [];
   if (forRelease.length === 0) {
diff --git a/review-enrichment/test/posthog-release-validation.test.ts b/review-enrichment/test/posthog-release-validation.test.ts
index 9569c76692..ef3813fdf4 100644
--- a/review-enrichment/test/posthog-release-validation.test.ts
+++ b/review-enrichment/test/posthog-release-validation.test.ts
@@ -105,7 +105,11 @@ test("validatePostHogRelease falls back to statusText when a failed response bod
 });
 
 test("validatePostHogRelease accepts a bare array response body (not wrapped in {results})", async () => {
-  const fetchImpl = async (): Promise<Response> => response([{ release: "loopover-rees@abc123", failure_reason: null }]);
+  // The real error_tracking/symbol_sets API returns `release` as a NESTED OBJECT
+  // ({id, hash_id, created_at, metadata, version, project}), never a flat string -- these fixtures use that
+  // real shape throughout this file (see releaseIdentifier's own comment in the source for why).
+  const fetchImpl = async (): Promise<Response> =>
+    response([{ release: { project: "loopover-rees", version: "abc123" }, failure_reason: null }]);
   const result = await validatePostHogRelease(validationEnv(), fetchImpl);
   assert.deepEqual(result, { release: "loopover-rees@abc123", symbolSetCount: 1 });
 });
@@ -123,7 +127,33 @@ test("validatePostHogRelease treats a response body that's neither an array nor
 });
 
 test("validatePostHogRelease fails when no symbol sets match the target release", async () => {
-  const fetchImpl = async (): Promise<Response> => response({ results: [{ release: "some-other-release" }] });
+  const fetchImpl = async (): Promise<Response> =>
+    response({ results: [{ release: { project: "some-other", version: "release" } }] });
+  await assert.rejects(
+    () => validatePostHogRelease(validationEnv(), fetchImpl),
+    (error) => {
+      assert(error instanceof PostHogReleaseValidationError);
+      assert.deepEqual(error.failures, ["no symbol sets found for release loopover-rees@abc123"]);
+      return true;
+    },
+  );
+});
+
+test("validatePostHogRelease fails when a symbol set's release is null (skip_release_on_fail path)", async () => {
+  const fetchImpl = async (): Promise<Response> => response({ results: [{ release: null }] });
+  await assert.rejects(
+    () => validatePostHogRelease(validationEnv(), fetchImpl),
+    (error) => {
+      assert(error instanceof PostHogReleaseValidationError);
+      assert.deepEqual(error.failures, ["no symbol sets found for release loopover-rees@abc123"]);
+      return true;
+    },
+  );
+});
+
+test("validatePostHogRelease treats a release object missing version or project as non-matching", async () => {
+  const fetchImpl = async (): Promise<Response> =>
+    response({ results: [{ release: { project: "loopover-rees" } }, { release: { version: "abc123" } }] });
   await assert.rejects(
     () => validatePostHogRelease(validationEnv(), fetchImpl),
     (error) => {
@@ -136,7 +166,9 @@ test("validatePostHogRelease fails when no symbol sets match the target release"
 
 test("validatePostHogRelease fails when a matching symbol set recorded a failure_reason", async () => {
   const fetchImpl = async (): Promise<Response> =>
-    response({ results: [{ release: "loopover-rees@abc123", failure_reason: "could not parse sourcemap" }] });
+    response({
+      results: [{ release: { project: "loopover-rees", version: "abc123" }, failure_reason: "could not parse sourcemap" }],
+    });
   await assert.rejects(
     () => validatePostHogRelease(validationEnv(), fetchImpl),
     (error) => {
@@ -151,9 +183,9 @@ test("validatePostHogRelease succeeds when at least one matching symbol set has
   const fetchImpl = async (): Promise<Response> =>
     response({
       results: [
-        { release: "some-other-release", failure_reason: "unrelated" },
-        { release: "loopover-rees@abc123", failure_reason: null },
-        { release: "loopover-rees@abc123" },
+        { release: { project: "some-other", version: "release" }, failure_reason: "unrelated" },
+        { release: { project: "loopover-rees", version: "abc123" }, failure_reason: null },
+        { release: { project: "loopover-rees", version: "abc123" } },
       ],
     });
   const result = await validatePostHogRelease(validationEnv(), fetchImpl);
@@ -164,8 +196,8 @@ test("validatePostHogRelease counts every failed symbol set, not just the first
   const fetchImpl = async (): Promise<Response> =>
     response({
       results: [
-        { release: "loopover-rees@abc123", failure_reason: "a" },
-        { release: "loopover-rees@abc123", failure_reason: "b" },
+        { release: { project: "loopover-rees", version: "abc123" }, failure_reason: "a" },
+        { release: { project: "loopover-rees", version: "abc123" }, failure_reason: "b" },
       ],
     });
   await assert.rejects(
diff --git a/review-enrichment/test/posthog-upload.test.ts b/review-enrichment/test/posthog-upload.test.ts
index 6444014901..f1dbdcac3c 100644
--- a/review-enrichment/test/posthog-upload.test.ts
+++ b/review-enrichment/test/posthog-upload.test.ts
@@ -55,7 +55,9 @@ async function postHogApiServer(options: { failFirstAttempt?: boolean } = {}) {
       res.end(JSON.stringify({ detail: "internal error" }));
       return;
     }
-    res.end(JSON.stringify({ results: [{ release: "loopover-rees@abc123", failure_reason: null }] }));
+    // The real error_tracking/symbol_sets API returns `release` as a nested {project, version} object, not
+    // a flat string (see validate-posthog-release.mjs's releaseIdentifier for why).
+    res.end(JSON.stringify({ results: [{ release: { project: "loopover-rees", version: "abc123" }, failure_reason: null }] }));
   });
   await new Promise<void>((resolveListen) => server.listen(0, "127.0.0.1", resolveListen));
   const address = server.address();
diff --git a/test/unit/discovery-index/validate-posthog-release.test.ts b/test/unit/discovery-index/validate-posthog-release.test.ts
index 57510bc546..d9dee2424b 100644
--- a/test/unit/discovery-index/validate-posthog-release.test.ts
+++ b/test/unit/discovery-index/validate-posthog-release.test.ts
@@ -82,8 +82,13 @@ describe("validatePostHogRelease", () => {
     });
   });
 
+  // The real error_tracking/symbol_sets API returns `release` as a NESTED OBJECT
+  // ({id, hash_id, created_at, metadata, version, project}), never a flat string -- these fixtures use that
+  // real shape throughout (see releaseIdentifier's own comment in the source for why).
   it("accepts a bare array response body (not wrapped in {results})", async () => {
-    const fetchImpl = vi.fn().mockResolvedValue(jsonResponse([{ release: "loopover-discovery-index@abc", failure_reason: null }]));
+    const fetchImpl = vi
+      .fn()
+      .mockResolvedValue(jsonResponse([{ release: { project: "loopover-discovery-index", version: "abc" }, failure_reason: null }]));
     await expect(validatePostHogRelease(validEnv, fetchImpl)).resolves.toEqual({ release: "loopover-discovery-index@abc", symbolSetCount: 1 });
   });
 
@@ -95,7 +100,23 @@ describe("validatePostHogRelease", () => {
   });
 
   it("fails when no symbol sets match the target release", async () => {
-    const fetchImpl = vi.fn().mockResolvedValue(jsonResponse({ results: [{ release: "some-other-release" }] }));
+    const fetchImpl = vi.fn().mockResolvedValue(jsonResponse({ results: [{ release: { project: "some-other", version: "release" } }] }));
+    await expect(validatePostHogRelease(validEnv, fetchImpl)).rejects.toMatchObject({
+      failures: [`no symbol sets found for release loopover-discovery-index@abc`],
+    });
+  });
+
+  it("fails when a symbol set's release is null (skip_release_on_fail path)", async () => {
+    const fetchImpl = vi.fn().mockResolvedValue(jsonResponse({ results: [{ release: null }] }));
+    await expect(validatePostHogRelease(validEnv, fetchImpl)).rejects.toMatchObject({
+      failures: [`no symbol sets found for release loopover-discovery-index@abc`],
+    });
+  });
+
+  it("treats a release object missing version or project as non-matching", async () => {
+    const fetchImpl = vi
+      .fn()
+      .mockResolvedValue(jsonResponse({ results: [{ release: { project: "loopover-discovery-index" } }, { release: { version: "abc" } }] }));
     await expect(validatePostHogRelease(validEnv, fetchImpl)).rejects.toMatchObject({
       failures: [`no symbol sets found for release loopover-discovery-index@abc`],
     });
@@ -103,7 +124,9 @@ describe("validatePostHogRelease", () => {
 
   it("fails when a matching symbol set recorded a failure_reason", async () => {
     const fetchImpl = vi.fn().mockResolvedValue(
-      jsonResponse({ results: [{ release: "loopover-discovery-index@abc", failure_reason: "could not parse sourcemap" }] }),
+      jsonResponse({
+        results: [{ release: { project: "loopover-discovery-index", version: "abc" }, failure_reason: "could not parse sourcemap" }],
+      }),
     );
     await expect(validatePostHogRelease(validEnv, fetchImpl)).rejects.toMatchObject({
       failures: ["1 symbol set(s) for release loopover-discovery-index@abc recorded a failure_reason"],
@@ -114,9 +137,9 @@ describe("validatePostHogRelease", () => {
     const fetchImpl = vi.fn().mockResolvedValue(
       jsonResponse({
         results: [
-          { release: "some-other-release", failure_reason: "unrelated" },
-          { release: "loopover-discovery-index@abc", failure_reason: null },
-          { release: "loopover-discovery-index@abc" },
+          { release: { project: "some-other", version: "release" }, failure_reason: "unrelated" },
+          { release: { project: "loopover-discovery-index", version: "abc" }, failure_reason: null },
+          { release: { project: "loopover-discovery-index", version: "abc" } },
         ],
       }),
     );
@@ -125,7 +148,12 @@ describe("validatePostHogRelease", () => {
 
   it("counts every failed symbol set, not just the first one found", async () => {
     const fetchImpl = vi.fn().mockResolvedValue(
-      jsonResponse({ results: [{ release: "loopover-discovery-index@abc", failure_reason: "a" }, { release: "loopover-discovery-index@abc", failure_reason: "b" }] }),
+      jsonResponse({
+        results: [
+          { release: { project: "loopover-discovery-index", version: "abc" }, failure_reason: "a" },
+          { release: { project: "loopover-discovery-index", version: "abc" }, failure_reason: "b" },
+        ],
+      }),
     );
     await expect(validatePostHogRelease(validEnv, fetchImpl)).rejects.toMatchObject({
       failures: ["2 symbol set(s) for release loopover-discovery-index@abc recorded a failure_reason"],