OP-1 Field USB charging on/off

Hi folks,
I connected op1f to ipad via usb-c to send midi out of ipad app to op1f. I didn’t want to drain ipad battery so I toggled the charging off on op1f (shift+com and press orange encoder so the lighting indicator has blue/grey background). Anyway the op1f is still being charged - I checked the battery status and also the led next to power switch is orange.
Am I doing anything wrong? Is this known behaviour/limitation?
Many thanks!

…the same behavior happens while connecting to mac

Hey man! I am having same issue. When plugging my OP-1F into a usb c hub hooked up to my iPad and tx-6 I am getting some crazy feedback. I could eliminate it by unplugging the field, but turning off the charging in the shft+com menu did not work. Figure anything else out?