Ultimatum skitterbots block enemies from spawning.

Hello,

i have been playing ultimatum since a few hours and the same bug keep reappearing every few maps.

I believe i ran about 20 ultimatums,and 3 of them where bugged.
Always when you need to slay monsters or defend the altar.

the wave starts as normal,and after a while monsters stop spawning and only 2 skitterbots remain.

They just run from one side to the other,turn red,disappear and respawn somewhere random.

They are very hard to hit with traps and just regen their energy shield everytime.

on this last run at happend first around round 7,now i'm at round 9 and ive been on this round for the last 10 minutes.

Normally i would just skip this ultimatum like i did the last 2 times,but there actually is some good stuff in this one and it's really frustrating.


I have no idea if this is a known bug,but i would like to let this known because i can't be the only one experiencing this.

Is there a way to upload a video so i can show this?