My iPhone is quite old so it gets goofy with LTE and BlueTooth a week after use if you don't reboot it. The problems also translate to my Watch. This week my AirPods started to cut in and out and what was happening was my phone (connected to CarPlay in my truck but parked near where I work just in borderline range of my Watch) was connecting and disconnecting to my watch/Pods causing the music to stop and go. Had to go and turn off Bluetooth on my phone to get them to behave.
My Bluetooth on my phone crashes if it runs out of memory (the icon also vanishes from status bar) and my AirPods will not connect to the phone period if that happens. They also won't connect to my watch if I open more than 5 apps on the watch (runs out of memory, and stops connecting to anything othe than wifi). That was what made that unusual ball bouncing noise out of my AirPods a few weeks ago. Some kind of 'can't find a nearby device' sound.