Even if I create a new UGC block, it doesn't get added

[Luca-LSEG]

For example, when I design a staircase block and create a new item, it is successfully made. However, if I try to design another staircase block and add it later, it doesn’t get added

[AngeloTadeucci]

should be fine with this pr

• Fix UGC Templates stacking #421