There's definitely something fishy going on there. Here's my experience using an iPhone 5...
Bluetooth track and artist information sometimes worked in IOS 6. It was good in 6.1, but was broken after that. Only songs from the music app would display track/artist info. I was pleasantly surprised to see that in IOS 7.0, all Bluetooth information was displaying perfectly for any app (slacker, Pandora, etc...). However all subsequent upgrades to 7.01, 7.02 and 7.03 have all broken the Bluetooth display again and only the music app itself displays track info. But I found a very strange wor