I have this problem constantly when I try browsing the web while listening to music. It doesn't happen on every page, but probably somewhere around 80% of pages will cause my music to stop playing. This happens with both streaming music via the Pandora app, and when I'm playing mp3s from my SD card through the native music player app. Does anyone know of a setting, either in Firefox, one of the other apps, or universally in the Android settings, that can stop this from happening?
This is an LG Optimus F3Q running 4.1.2.