I found a small undesirable behavior. I have standard 250ms delay for volume and 5s delay for autoplay. If the phone connects to Bluetooth device only for a very short time (for example if I have to move the car in a parking) it continues triggering actions even if the device disconnects in the delay time.
So the actions became:
device connected
increasing volume
device disconnected
autoplay
And music starts playing at full volume from loudspeaker.
https://mail.google.com/mail/u/0/?hl=de&shva=1#label/%40darken.eu%2Fsupport/162856286b55dda8