Hi Guillaume,
We’ve submitted a fix in PCGAssetExporterUtils which wasn’t properly handling existing assets (CL 42428260 in UE5/Main). This fix will make it in to UE 5.6.
You should probably still be saving this asset as in your example project the asset ends up in the /Temp and will not be persisted, so I am not sure what will happen when you cook the game.
Cheers,
Patrick