Not 100% sure how it happens, but after sometime Slime Pit(Dryad tower) just stop attaking. There was a boss atking a blockade and the slime pit dind't atk him, the same with normal enemys in other lanes. (Energy was in 86%, World tree halfed, trap was behind the boss.)
Expected Results: See if it really happens, and if so, fix.
Happened to me plenty of times. If a mob goes "behind" the trap as to cross over it to the other side, slimes just stop attacking frequently