I am having trouble with this map, from the beginning its been hard to work with, but i was able to get around it, now it seems my spawn points are always at least 30 meters in the air. and everything I place there is "out of playable bounds.
You need to test your y axis's. Use the green bottles at different y denominations starting at -50 to 50. Some map y axis do not start at the ground base of the map. This is a problem as 0.0 is a spawn axis default which spawns the enemy on the highest level solid object the npc or object falls to.