See image above specifically focusing on the right side — this is what appears after the iPad screen is turned off and back on again. The issue is resolved when leaving OSC (Safari window on iPad) and re-opening. Odd that some buttons & knobs are unaffected while others are more affected.
I'm not sure sure there's anything I can do about it, it looks like a rendering bug in safari. Maybe changing the orientation would force safari to redraw this part of the screen ?
Sadly it doesn't. Bummer, but thanks!