Issue with actor references serialisation, loading old game saves

Hey unreal devs!

This is more of a engine question:
I use to save actor references but I cannot load them now, do you have experience with the serialization system?
The function StaticFindObjectFastInternalThreadSafe return null given the right actor name .
When GetObjectOuterHash(ObjectName, (PTRINT)ObjectPackage); is called with the right names and package, nothing comes from it.

I dunno if it’s due to 4.25 update or a change in my blueprint class.