Indeed. Mine has gone even weirder now, it stops and starts to fetch automatically even more frequently now, but most of the time it refuses. And no response to the bug report either... This needs to be fixed ASAP, I'm missing a lot of important mails..
Only way I know I have an email in my trusty iPhone 6S+. I got no response to my bug report either. This am woke to "mail last checked at 8:34 yesterday.