Mail App Keeps Opening By Iteself

Almost every hour or so, the Mail App opens itself into the foreground of whatever I happen to be doing. This is super annoying as it interferes with my work. It also loves to open when I am in a full screen video or some other full screen app. I have tried various solutions and have unchecked the box "prefer opening in split view when in full screen." I am stumped by this behavior and would appreciate any help.