If you mark emails are read in non-current folder, it temporarily marks emails as read in the current folder
Pretend you are in the Inbox folder and you have a folder called "Folder1" with an unread email in it.
1. Choose the arrow next to Folder1 and choose "Mark emails as read"
2. Notice that all unread emails in Inbox are marked as read (incorrect) and Folder1 still has the counter for unread emails unchanged (also incorrect)
3. Select another folder like Spam then go back to Inbox
4. Now the view is correct, with unread emails in Inbox not being touched and the unread email in Folder1 being marked read and the counter being 0 or not shown
Something is strange in that intermediate state. The current folder is temporarily marked as all emails being read, which in incorrect. Only the non-current folder you selected (Folder1) should have emails marked read.
Artur Bacu
shared this idea