Ever since I got my new car stereo, a Pioneer DEH-S5200BT every now and then when the Galaxy S 21 phone connects to the Bluetooth the volume goes up and down really fast for about 10 seconds and other times it just plain goes all the way down then i have to dig my phone out and turn the volume up. it’s really annoying. When I tested my friends BT speaker out it did the same thing with the volume going up and down really fast. but my other two speakers doesn’t do this or my various BT earbuds. Anyone else have this problem? The car stereo was reset many times and repaired tp the phone many times.