One possibility to prevent the enemy from jumping, when it can't jump far enough to make it over the gap, you can add two more detector objects, placed even farther out.After-gap solid detector
This detector confirms that there's a near-enough solid object on the other side of the gap, that the enemy could get to it by jumping.
Notice, though, that this will detect a flat landing spot as a solid, but it will also detect a vertical wall the same way, so it's not good enough by itself. (Unless you don't mind the occasional mid air face-plant into a wall) Clear jump path detector
This detector confirms that there's open air above the landing spot, and open air in the jump arc the enemy would take to get there.
This helps the enemy distinguish between a true landing spot, and a vertical wall. It also prevents them from jumping if the ceiling is too low to make the jump.