I closed a question earlier: https://drupal.meta.stackexchange.com/questions/2228/serious-issue-with-this-site
As soon as I did so, 3 of the 4 answers were automatically locked and deleted by the Community user. The answer that wasn't deleted belonged to a moderator, and I assume that's why it wasn't deleted.
Even though the question isn't constructive the answers were good, so I undeleted and unlocked them.
Is this the expected behaviour? Does it have something to do with the question having been migrated from the main site? I seem to recall a post on Meta Stack Overflow discussing something similar a while back but I can't seem to find it now.