It does and I do
Admin can specifically tell you all the technical rules behind it but yes, sometimes threads need to be "approved" before they are publically visible. Particularly if you are fairly new and have a low post count.
It doesn't mean you did anything wrong or anyone complained (I promise)! I check as often as I can but I can't be on 24/7 so sometimes posts don't get approved until morning (I always check first thing).