Sorry for the late reply.
Just to confirm, can you please share how you are setting up the SubTree of the root Behaviour Tree?
Are you using a variable for the “Behaviour SubTree” parameter of the SubTree node (as per the image bellow) and then change the variable in runtime, or some other way around?
[attachment file=”SubTreeParameter.png”]
I am just trying to reproduce the problem.
Please let me know how. 🙂