Okay this only happens when you have allow the Moderator to place units. Also one of the Zeus tends to crash every so often at complete random(usually happens when the other Zeus deletes something, at least every time i asked the crashed person, that's what they said)
These problems happen about 2x more often on Custom Zeus, but the fact they do happen on official mission, was enough for me to not try and find a solution. For our mission we unlinked the Zeus's for now until it no longer happens.
This problem may or may not be related to http://feedback.arma3.com/view.php?id=18267 but i'm inclined to think that they are unrelated.