Weird thing happened today -- curious what would have caused this...

All of a sudden today, with no changes that I am aware of, instead of
the listing title all of my listings showed
"listing" on the homepage, etc.

I went to admin -> main category -> Listing title builder and it was
still set as I had it previously: Category, model, Length.

I didn't know what else to try, so I simply hit "save"

And then all was well.

A bit confused though as I wonder what would be some things that could have caused this to happen?

(Earlier today I changed the cache from 'disabled' to 'file cache' but it seemed fine immediately after that; I was working with adding a content box (html) for the my messages page; other that those items, I don't see what I could have done that would have caused it today, so just curious what would create such an odd issue..)