diff --git a/src/coreclr/debug/shared/dbgtransportsession.cpp b/src/coreclr/debug/shared/dbgtransportsession.cpp
index 2df265f22b869e..596794cb9b1a44 100644
--- a/src/coreclr/debug/shared/dbgtransportsession.cpp
+++ b/src/coreclr/debug/shared/dbgtransportsession.cpp
@@ -2203,6 +2203,7 @@ DWORD DbgTransportSession::GetEventSize(DebuggerIPCEvent *pEvent)
     case DB_IPCE_AFTER_GARBAGE_COLLECTION:
     case DB_IPCE_DISABLE_OPTS_RESULT:
     case DB_IPCE_CATCH_HANDLER_FOUND_RESULT:
+    case DB_IPCE_SET_ENABLE_CUSTOM_NOTIFICATION_RESULT:
         cbAdditionalSize = 0;
         break;