Incoming phone call is going to the phone audio instead of my blueetooth connected headset I have just taken a call and was using my bluetooth headset. It has been connected the entire time since the call ended.  A new call came in and the iPhone audio was chosen instead of the headset.
This has been the pattern. It is annoying and confusing to the caller who has to wait while I re-select the headset audio . Note the headset did not need to reconnect: it was already connected/available.
Why is the headset not retained as the default audio device? Is there a configuration to achieve this?
I am on an iPhone6s on ios 14.2
I have had this happen throughout the iOS 14, even back to the betas. I reported it using the “Feedback” app but it still persists even in 14.2.1.
Your best option is to report the bug using this webpage:
https://www.apple.com/feedback/iphone.html