well, things do come loose some times over the yrs, it might have been walking out a little each yr and just finally got to the point it was showing a sign you seen
its also why a lot of folks, when they do a good cleaning go over every thing to make sure there tight
as just never know till you check some times, and its a good way to find things other wise might be missed!
at least it was a easy fix, which is always nice