Reassigning AI Controller doesn't run Behavior Tree

Whenever an enemy dies, I put the empty AI controller in an array. When I spawn a new enemy, I look if there is a controller inside the array, and if yes, I use it. But the reassigned AI controller does not run the Behavior Tree. Is there something wrong with my setup? See screenshots.

Can’t get this to working, no matter what. Since there is no option to simply remove a controller that isn’t needed, I think this is the only way to be efficient? But it doesn’t seem to work…

Did anyone else get this to working? Possessing another actor after the first one gets destroyed? I can do all kinds of checks like “controller is valid”, everything returns true. I’m basically resetting every variable manually. The AI is simply not doing anything. Should I enter a bug report for this?