Hello and sorry for the late reply!
Can you please let me know the exact steps to reproduce this problem?
This is what I have tried and seems to not reset the variables:
1. I created a prefab asset (with a blackboard) and added some variables.
2. I create a prefab variant from that prefab asset in the project (right click -> create -> prefab variant) and added some extra variables.
3. The original prefab’s variables are not reset on the variant and seem to be retained.
Using Unity 2018.3.0f2
Please let me know of the steps to reproduce!
Sorry for the late reply and thanks for the video.
I can confirm that this happens on the latest version of Unity 2018.3.6f1, while it does not happen in for example version 2018.3.0f2 …
Thus, aparently, Unity is still changing things as far as the new prefab system and their serialization goes to a point that it gets anoyingly inconsistent unfortunately :/ . I need to dig into this some more and find what could be causing this, or if maybe its a Unity bug introduced in latest Unity version, because the Blackboard serialization if actually very simple, just using the Unity OnBeforeSerialize and OnAfterDeserialize callbacks. Nothing really fancy.