"Run Behavior" in a Behavior Tree don't work if the Blackboard is not the same. Bug ?

Hello, I lost some hours on this.

I have a Behavior Tree BT_MacroAI that use BB_MacroAI as Blackboard.

And I have a Behavior Tree BT_MoveAndGrabMicro that use BB_MoveAndGrabMicro as Blackboard.
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If I play the game BT_MacroAI fail at Run Behavior without reason.
But If I change in BT_MoveAndGrabMicro the Blackboard from BB_MoveAndGrabMicro to BB_MacroAI it work. BB_MoveAndGrabMicro use BB_MacroAI as parent.

This is a bug?