@all: Happy new Year!!!
@TonyW: as your Bluetooth Dongle (inbuild Bluetooth) seems not recognized: Have a look at the „Raspberry Pi Settings“ Page and see if Bluetooth is disabled. Is the Max2Play web interface header telling that you have a „Raspberry PI 3“? Maybe you are running on a RPi 2?
@mnvelocitypilot: the long list in your Squeezebox Server playlist and the bluetooth app, that “reasserts” itself, is triggered by the autostart of the Bluetooth („Autostart Bluetooth-Streaming in Squeezebox Server“). Disable this setting at the bottom of the Bluetooth page (restart RPi), and manually start the Bluetooth Stream in your Squeezebox Server to see if this works better. During testing I had a similar problem with the inbuild bluetooth on RPi 3, when the BT-signal was not very good. The dropping of the BT-signal and reconnects confuse the script, that checks for connected audiostreams and starts/stops the streaming in Squeezebox Server. You may try to place your smartphone right beside your PI and the problem is gone – or use an external Bluetooth stick with better performance to improve the distance. I will also try to improve the autostart script with some delays to react little slower, when a stream is interrupted – this should solve it in the next version of Max2Play.