Found a reason why purge bug out after a few waves

[Blyker]

I have seen quite a few times that a few waves of a purge were able to reach my base but that i would get a message that they can’t reach it and will retreat.
I have found the reason for this: The wave spawns inside a tent in the base and the Stygian Soldier fighters of the base are standing in front of it blocking the wave. Mostly happend when the tent spawns right behind the treasure chests.

[Blyker]

Here a screenshot of a partial block. In this case i did not get the message but the purge stopped. When i shot that group with a noxious arrow it caused both the wave thralls and the Stygian Soldiers to move making the purge progress as normal.