Headphones automatically lower volume in the sun

I researched this community for answers regarding headphones lowering automatically on their own and discovered it's when you're using wired Bluetooth lightning headphones, if they have a volume up and down switch on one of the cords, when that switch is in the sun, it will automatically lower your volume to zero. You can pump the volume back up and then keep your hand over that switch for the duration of you being in the sun but that is ridiculous. Two questions why does this happen, and are there any wired cables for lightning port that do not use Bluetooth and that come without the volume up and down switch on the cord? To me that's the only solution or possibly cover up the volume up and down button with some black electrical tape and see if that helps. My old android looking better every day.