Characters being pushed through/over walls

[xTLRxPrototype]

Hi, I have walls and a gate (level 3) around my base, and sometimes when I am under attack, my engineers go to fix the main gate, but if enough of them (10+?) go to fix the gate, they start getting pushed thru to the other side and get KO'd from the mob of enemies and friendly fire of turrets from above.

Very rarely, a enemy will get pushed thru the gate, make it to my turret defense up on the wall and attack them. Once they are attacked, my people run up to go heal the guy, and if enough of them crowd up on the wall, they teleport down and outside the perimeter of my base.