My LG G2 D802 has been having problems with bluetooth lately. Started with 4.4.2 android and same with lineage 16.0
You turned the bluetooth on and it would just say activating and wouldn't really turn on. A restart would cure it, then restarts weren't always effective, now it has stopped working altogether. No app tricks ever worked neither clearing cache and data. And the message bluetooth has stopped working will appear erratically if using phone.
Cell Phones - LG
Answers & Comments
Take it to a phone repair where they can help you couple it with new components. they take out the old one and put some new ones in it.
send it to the manufacturer for easy access to it so they can help you with it. you could get a new one sent to you.