I've had issues with songs playing randomly. Just yesterday my phone started playing music in my pocket without any inputs! And there's no way my thigh unlocked my phone. I was out in the middle of a park and all of a sudden, music started playing. I turned it into a mini dance party with friends, but it was a definite bug.
With Bluetooth, I haven't observed these issues prominently, but I do remember it happening once like you described. While connected to Bluetooth normally, you paused the song using your Bluetooth device. Then after a few moments ir resumed playing by itself. I think that's what you're describing.