A squadron of custom infantry were unable to attack a particular enemy. The army will walk on top of the enemy and no combat will start. Other combat was working fine.
http://pastebin.com/f170a5a23
I have had this a couple of times.
I've also seen it, with my sovereign unable to attack another sovereign.
Probably related to this issue.
Quite possibly. I've noticed sometimes my units were unselectable at first then realized I was clicking in the "right" area. They were in another location almost. Quite strange.