I follow a nearly identical flow several times a day to connect bluetooth headphones to my laptop.

- Turn on headphones * Laptop connects immediately and uses the HSP/HFP mode (works!) * Trying to select A2DP appears to work, but no audio will play - Disconnect the headphones using the Bluetooth manager - Reconnect the headphones using the Bluetooth manager - Select A2DP, this now works.

https://bugs.launchpad.net/ubuntu/+source/bluez/+bug/1438510

Separately, many web videos will stop playing and refuse to play when the Bluetooth audio device is selected.

https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1589008