Mark as read for Mail on lock screen clears ALL email notifications, not just the one I mark as read.

As the title suggests, when I pick up my iPhone 7 Plus since running iOS 11, if I mark any email as read, all other email notifications disappear meaning I have to then unlock the phone, go into mail and check the emails and mark as read from there. A small issue, but not as it’s meant to be so is somewhat frustrating. Any suggestions beyond restarts and restores??