Quite often and not consistently for all unread emails, my emails show as read.  I don't have any other reason to believe I'm being hacked.   My settings for Mark mail as read are "Only when opened in a separate window".  Yet some messages received only minutes ago show as unread even though I have not read them.  the only email account in Outlook for Mac is my gmail account.  I've removed notifications on all other devices for email just in case and also deleted any 3rd party email apps from all devices to see if that was the culprit but the problem still persists.  Any ideas?