Hey there @SVR33! I’ve seen FBlueprintCompileReinstancer errors most commonly when you have some form of circular dependency in your code.
This line in particular stands out [2026.02.17-00.55.19:083][ 0]LogInit: Display: LogOutputDevice: Error: OwnerClass should not be ‘REINST_’! This means that a REINST class was parented to another REINST class, causing unwanted recursion!
The best way to find the culprit would be to check the full logs (under Saved/Logs) and look for the blueprints being compiled immediately before the error, as it should attempt to compile it regardless. This should point to either the parent class or child class that contains one half of the circular dependency. You will have to remove the references one way to resolve it.
However if that’s not the case, there are some other reasons this could occur such as prebuilt data or a corrupted blueprint. Thread below has some other workarounds: