IntelliLink Issues

Hello all, I am new to the forum and have a question regarding an issue that we are having with my wife's IntelliLink system. We have a 2014 SLE-2 and when her iPhone is paired with the system and she goes into Facebook or other apps it automatically switches the radio over to the Bluetooth input. It has never done this before and only started about a month ago. It's obviously not an issue while she is driving, but most of the time when we go out I drive and she is on her phone we have to constantly change the source back to whatever we had on because it will randomly switch to Bluetooth input.