Alright, well after a few days of trial and error, I was finally able to ascertain that the game framework I am using (Horror Engine, as a starting point) saves all of the existing structs that dictate game play status events on actors in the cache. Here is one of the culprits:
While I was not accessing or using these to restore the save (yet) I believe storing these structs in the save file might cause some sort of referencing error, it is interesting though that it would only occur once I tried to load in a new Data Layer rather than when I load the save game object from disk. Even if I ensured each actor in the data layers was completely loaded before accessing these horror event objects in the save, it would crash loading the layers ( I checked by using the World Partition Subsystem - Is Streaming Completed node for the location of every actor just to debug).
Looking around it seems using Get Object Name isn’t really recommended for gameplay logic bc they can change at runtime, so it is not guaranteed to be persistent across engine sessions. Also - this logic in general won’t really work when loading the save, since I will need to restore interactable object states that may not be in the current loaded or active Data Layers. Rather tham having a single “save component” find all actors and save/set their state on saving and loading, I will probably rewrite this whole system so interactable actors will instead load their saved state from the save component on their Begin Play event, since this is invoked every time an actor is reactivated in a Data Layer.