I just started a mission in a snowy area and got lucky, being able to kill 2 aliens without barely moving from the transport. After finishing moving my men and ending my turn (discovering another alien to the top-right), I see the discovered alien run into the fog of war and then the "Hidden Movement" overlay pops up and doesn't disappear (I left it for at least 10 mins).
Restarted game, tried again (killing the 2 aliens) saved and then finished movement. Locks up again. Tried a third time (from the save after killing the 2 aliens) without moving my troops. Still locks up. Tried loading the auto-save at the start of the combat, end turn immediately. Brief "hidden movement" popup, then alien in-front moves, my men perform reaction fire (only minorly damaging alien, while killing one of my soldiers and injuring a few others). Hidden movement screen appears again, hear some footsteps, locks up.
I would attach the save files, but the page keeps coming up as "forbidden" for me so I've placed them on DropBox @ https://www.dropbox.com/sh/96d15bk929pu9ci/2qkT2LPYDX
