PeensandNeedols

I realise this was quite a while ago, but I'll just add that I'm still playing XCOM2 in 2020 and the bug has happened to me multiple times over multiple playthroughs, so I don't believe a patch will ever come to be released. The wisest course of action when starting an Ironman playthrough, would be to simply disable the mission. Something I've noticed about the bug, though, is that the level is still very much "beatable", but there's one MEC corpse ragdolling around in a certain corner of the map. I believe this to be the reason why you can't make any moves or end your turn. However, after a few minutes of just waiting around, eventually the game'll let you have your turn. Don't expect everything to act like normal afterwards though. The same process will be repeated until you get all of your soldiers out of the area and into the next, that being the roof. So, yeah. That's my take on it.