System automatically increase volume

if you turn off the volume completely using the control in the control center, the system will automatically increase the volume again. This is tested with many iPhone 14 pro max and 15 pro max in Germany. This doesn't happen all the time, but sporadically. I've already been to Apple Genius Bar about this and they determined that it is a bug. As an example, try turning the media volume up and down in the Control Center making it silent and loud again 20-30 times in a row. You won't be able to do this without the system automatically making it louder again. This happens with iOS version 16 and 17, so with both.