I was using my bluetooth headphones (Bose QC35II) as usually but this week I had to unpair it and when I paired it again it didn't get recognized as a sound card anymore. The headphone remains with a intermittent light like is trying to connect but the system shows it as connected.

Other bluetooth stuff like a mouse and a keyboard are working and pairing with no problems.

I don't know what happened, maybe a kernel or firmware update?

System Info:
[*] kernel 4.15.0-32-generic
[*] KDE 5.13.4
[*] Wifi/Bluetooth Intel 8265

I had the same issue with the same headphones.

I managed to get them to connect properly by
disconnecting, unpairing and making sure they were not remembered;
Then clearing the saved connections from the headphones (hold the on switch to the max for 10 seconds);
Editing the Bluetooth settings to not work in LE mode (see here https://askubuntu.com/questions/833322/ ... -bluetooth);
Installing bluemam and using blueman-assistant to set them up;
Switching BT back to LE mode;

Some of the steps might not be necessary, but at least I got them working.

Good luck!

Thanks, it worked!!

I just did the steps in the link you posted and it worked. Just with that is enough.