Service [Q] Bluetooth support and pie controls


My Nexus 4 was working just fine on stock jwr66y, bluetooth connected in car and worked as expected.
All ota updates after that and zips have totally stuffed it. Just connects for 5 seconds then disconnects for 5 seconds, repeat.
I now have pa 3.99 rom installed which goes back to Android 4.3 so the bluetooth works ok, but I can't for the life of me get out of pie controls. I take out full screen, go into settings and set Trigger area to none (disable) and nothing happens, no controls at the bottom of the screen. Doing a reboot does not restore controls and I have to revert to pie controls.
Anyone got any suggestions, I can live with pie controls but Google just advise that they cannot guarantee bluetooth will work with every installation. It was working fine guys, you broke it.