In fact, you made me think to try something.

Ever since I upgraded the firmware on the BC127, it has had a new problem:
- In either "new" or "old" mode both...
- It always is stuck in pause mode forever, and pressing the Play button on the car stereo does nothing.
- Also presing the pause button never sends the pause or stop command (probably because of the above).

However...
- in either "new" or "old" mode both...
- When I unpair the device from the car stereo using the car stereo's touchscreen controls to perform the unpairing...
- An AVRCP_STOP command is sent to the BC127 instantly with no delay, and then the unpairing occurs instantly thereafter.

So the stereo itself, and the handshaking system, actually have no compunctions about sending AVRCP commands at their core. It can do it.

So the delay is introduced somewhere else for some other reason. Something about the BC127's configuration or protocol is confusing the car stereo. Not sure what, yet.