You are executing a task, finishing it, then checking the behavior tree next frame and running the same task. This is not the same as ticking even though it seems like it would be. It is best to avoid spamming tasks back to back in that way because if the ticks are not guaranteed to happen some things won’t work properly, like the add movement input node. Also with more developed AI you probably don’t want to run through the behavior tree every frame if not needed. If you use event receive tick without finishing the task then it should run every frame and look smooth. If you use a branch and a delay until next tick node to keep executing the task until a condition is met, it would tick smooth.
Edit: That’s the reason for the behavior tree setup not working. I’m not sure about the mouse issue but if you hover over any button in the editor while the game is running it does cause an fps drop. Idk if thats something to worry about yet.