I just saw the "freeze at end of combat" bug. I saw one of my islands at risk, so I sent a flotilla to it, not remembering that it was currently at max people; this resulted in me sending a zero-size flotilla (I've accidentally done this a few times before). Before it arrived, the enemy got there and conquered it, but just barely (2 attackers survived). My zero-size flotilla arrived, the combat screen popped up, one enemy was destroyed (I conjecture my flotilla was a siege flotilla; I can't seem to get any info about it now), and I'm now stuck at the combat screen with one enemy standing there and nothing happening.