When a diamond moderator locks a question, there's a choice to have it auto-unlock in an hour, a day, a week, or not at all. Generally, this function works fine.
However, I locked every post on this question for an hour, and while the question auto-unlocked an hour later, I had to manually unlock the answers. I doubt it's a cron issue because the question was the last thing I locked, so if it unlocked, everything else should have as well.
Furthermore, the lock box displayed a "Unlocks in xx minutes" note (visible to mods only, I think) on the question lock, but not on any of the answer locks.
On that basis, I'm pretty sure the timer lock on answers doesn't work. If it's supposed to work, please fix it; if there's supposed to be no timer at all, please make it work nonetheless, because it would be incredibly useful in situations like this.