I have noticed that when you use a State Tree Component in an Actor and overwrite the default Parameters of that Tree in the Details panel of the Component (see image), the changes are not reflected in the Actors that are already placed in a Level. They are updated however, if I delete the Actor from the Level and place it again. Is this a bug or what might be going on?
I have this exact problem in 5.8. Did you ever figure anything out about it?
Hello @roughneckmike and @Perfect_Human_Interface ,
If I understand correctly, this seems to be related to how Unreal handles instance data for actors that are already placed in a level. When you modify the default parameters of a State Tree Component in the Blueprint, those changes may not propagate to existing instances because they keep a serialized copy of their values. As a result, actors that were already placed in the level continue using the data they had when they were created.
If you delete and place the actor again, a new instance is created from the updated Class Default Object , so it picks up the new default values.
Additionally, there is an open Epic bug report (UE-282655) describing a very similar issue. The ticket confirms that, starting with UE 5.4, changes to the default values of Instanced UObject properties in a Blueprint are not propagated to actors already placed in a level, even when the level remains open. The issue is marked as a regression from UE 5.3, where those changes were correctly propagated to existing instances as long as the property had not been manually overridden.
Because of that, it is possible that what you’re seeing is related to the same regression and is not specific to State Trees.
Hope it helps!