So, invaded one of their nests, have killed a bunch, then suddenly I just keep cycling thru my players turns with no enemy stage. Whether I put them on overwatch, or end turn, or whatever, it runs thru all my team members, then pauses for couple seconds and then I’m back on my team’s turn again. Endless loop. And even if I fire at enemy, or completely skip turn, or any other option, it just keeps looping. I exited out finally by closing the game window.
The cause of this usually seems to be that an enemy has gotten trapped in the terrain and cannot move, or it has no idea where you are and so stays where it is rather than patrolling.
Did you destroy the building in the nest?
Edit: Here you got a video from the attack on the nest. For my taste, this guy has no idea what he’s doing.
But at least you can see how the mission is done.
I suggest you search every corner and little piece of terrain. It happen to me in a haven defence mission, I started looking into the buildings room by room and stall by stall. Only by pure luck I found the last crabman hidden behind the corner of a building in a corner of the map, and I had to have my operative step in the square next to crab to find it. They can hide really well, sometimes.