BUG?: iPhone Music player blares music playlist when starting Cityville Hometown app

When I start Cityville Hometown, it tries to load, takes a long time (contacting Zynga? via 3G network), then out of nowhere, the iPhone Music Player will start playing from my music list...at FULL VOLUME (and I always have my mute button set for NO volume)!

App bug or bug with iPhone Music Player? Happens intermittently, but is very repeatable (1 in 10 tries usually gets it triggered). BTW, this happened with iOS 4.3.2 and also with iOS 5 and 5.0.1. versions of the operating system.

Cheers,

applerucks