Shortly after I updated my iPhone 4 (on AT&T network) to iOS 7.1.1, I started getting "storage almost full" messages popping up. When I checked the available storage under settings, I saw that it was indeed down to 0. After synching to iTunes, I saw that the "other" category of data was taking up well over half of my 8GB of storage. After some experimenting, I noticed that it seems to be related to running the music app.When I run Music, the available storage shrinks quickly and has nothing to do with the actual size of the music files (it's the "other" files that take up room).
I've completely restored the phone from backup and this hasn't helped the situation. What's going on here?
Same issue over here on multiple iOS devices, conducted reset and restore multiple times now, after a couple of hours the devices run full again.