I just sent an e-mail to you!
I'm on the Unity latest version and with BD 1.5.8. You are suggesting to upgrade incrementally from this state, is that it? Or do I need to rollback the Unity version as well?
This was already happening with the older version (from around May 2018), the issue started when I upgraded the Unity version to the latest. Then when the issue started I upgraded to Behavior Designer latest version.
This is the error from the old Behavior Tree version:
I'm trying to edit my behavior after upgrading both Unity and Behavior Designer from a very old version (from around May 2018).
Behavior Designer: 1.6.3
Unity Version: 2019.2.17f1
NullReferenceException: Object reference not set to an instance of an object