The 3D Touch expalnation sounded plausible - but if it was true then it should be present on most of the other buttons in control center because you can 3D touch those too.I think it’s when you are using Bluetooth speakers/ Apple TV etc
Same here. Blue when using airplay, bluetooth speakers/headphones or wired (lightning) headphones.Playing over iPhone speakers, mine pulses lighter gray for a second. It changes to blue when using airplay, AirPods, and (sometimes) wired headphones, but it doesn't always stay blue either. Curious.
Well I sent Apple Support a direct message on twitter but they replied saying that they can’t view images on twitter so can’t see what I’m showing them :-/