Noticed this on my current campaign:
Certain militia which are unlocked by event, if attacked before the event, then relock when the unlocking event then fires.
Specifically, I've noticed this with Columbia and Clarksburg militias. Both have been attacked and have been unlocked, both have retreated to a safer place, both have then had events firing to free them after the attack and become locked again.
Could someone else confirm that this isn't me having a glitchy install and that there is a little bug afflicting some of the militias (certainly not all as I know other militias do not suffer this bug)?