Apple iPhone 12 not working correctly with Apple headphones & dongle when on phone calls

Apple iPhone 12 Mini has stopped recognizing my Apple wired headphones when I'm on on a call. The headphones are recognized correctly by other apps (e.g., YouTube). I'm using Apple headphones and an Apple lightning dongle. Other people have reported a similar issue and their threads have been closed with no resolution shown. Is there a resolution to this?

BTW I've tried options suggested in other threads to no avail.