Mann locked the thread here: http://www.scp-wiki.net/forum/t-577344/write-something-that-can-scare-me
For whatever reason, it didn't lock. (Echo was able to post in the thread.) Kain posted fifty minutes later also locking the thread. We don't know if was ever locked, came unlocked again later, or what. (It's locked successfully for now, verified by Echo trying to post in it; mods & admins can post in locked threads AFAIK, but senior staff & regular users can't)
Mann says it may have been because of his connection, but it's odd that both he and Kain failed to lock the thread before now.
Also, I could swear I've seen other locked threads come unlocked again completely on their own for no reason, but unfortunately I haven't documented anything and could be wrong.
SO, if anyone sees an instance of shenanigans with thread locking, please post here.