[v12.1] Randomly spawning & invisible aliens during base invasion

When the aliens invade the base, sometimes they spawn in random locations - like between two large squads of my troopers. There also appears to be an invisible alien in the central location that's probably supposed to be the reactor, since when you get the aliens in these random locations, the mission ends with a loss in a 1-2 turns. I have a guy in that room, but he can't see anything.

Elim,

Please check the known bugs sticky before posting, this is a known issue. Admiddetly the known bug list is long, took me a bit to find the links Here are 2 threads on this topic:

http://www.goldhawkinteractive.com/forums/showthread.php/2267-v12-Able-to-target-non-existent-enemies

http://www.goldhawkinteractive.com/forums/showthread.php/2412-V12.1-Invisible-alien

Huh, my previous reply didn't take. Anyway, I did check - this doesn't seem to be exactly the same bug. The main issue is that aliens are spawning in random locations on the base. And the two events are tied.

Spawning in different locations is indeed different.

The 2 threads I linked are about invisible aliens with only a shadow showing.