I was one of the fools who installed the iOS 7 beta onto a phone that I depended on with Google Authenticator. The app had a compatibility issue with that beta release that caused it to disappear all my 2FA seeds except, very fortunately, for my Gmail. There was a bit of a ruckus about this here https://news.ycombinator.com/item?id=6112077.

Since then, I always use at least two 2FA apps at the same time.