Incoming call banner notification issue iOS 14.2

When I am using my iPhone (SE 2nd ed. - iOS 14.2) and I receive a call, the new notification banner will appear at the top of the screen from where I can answer the call. 

When lifting the phone to my ear, the display turns off when the proximity sensor detects this. 

The issue however is if I then receive another notification while on the call - the screen will then turn on again while the phone is still held to my ear, activating the display and meaning I end up pressing buttons etc with my face on whatever screen I was on when the call came in. 

I have tested and have only experienced this when receiving calls and answering them through the notification banner. This does not appear to be an issue when making outbound calls, or if answering incoming calls when the phone is not being used. The problem also goes away if you disable the banner notification and go back to full screen for incoming calls, changeable in Settings > Phone > Incoming Calls.