If and element has backface-visibility:hidden on it because it's part of a flip card, adding backdrop-filter:blur(9px) breaks the backface-visibility:hidden property.  It's really super annoying as it works properly on everything else.  I'm begging you to fix it.  Because since the browser thinks both properties are compatible with the proper -webkit- prefix, one cannot even use an @media query to hide the backdrop-filter property on mobile.  Both are compatible so it won't trigger the media query.  Unless I'm just stupid (a real possibility) this is a bug and it's one stoping my code from working on iOS mobile which was my original target.