IOS15 notification issues

Hello - Since downloading iOS 15 several weeks ago, my various email applications are having their notifications silenced randomly. I’ll go three or four days and then realized that I haven’t been checking important emails because I’m no longer seeing red notification bubbles in the corner of the apps on my home screen. This is affected my Gmail app as well as my Hotmail app. If I turn the notifications back on I’m OK for a while but inevitably they’re turned off again without my consent. Have you encountered this problem with anyone else? Is there a known solution? I haven’t been able to find anything on other forums.