Since the most recent OS update (the one right before this last security update) my bluetooth has been acting weird. I will have a device connected and suddenly it will just stop receiving data (music will shut off or call will stop being sent through BT). Power cycling the connected device will make it reconnect, although there's never a disconnect shown on my phone. This happens with all 3 devices in my pairing list. If I open up bluetooth when the issue is happening, it will show connected with one device and trying to connect to another (distant, powered-off) device. Also, if I'm listening to music when it happens, the music player will show the song still playing, it doesn't pause it like it does when there's an actual BT disconnect.
Prior to the system update I had no issues and the phone would only connect with one device at a time. If it was paired with one it would not try to connect with anything else, even if another paired device was turned on within range.