Is this problem not returning for those who have "fixed" it?
I have finally gotten my new iPhone 7 Plus. I took the time to painfully set it up as a new device rather than restore from a backup. I wanted to eliminate any possibility of transferring a mail app bug over from the process.
So I added my exchange account to my vanilla fresh out of the box new phone.
Sadly, I can report the issue has occurred yet again in my Junk Email box. It took less than 24 hours. There were 4 messages in there. I clicked Edit and manually selected each message (no more Delete All for some reason in iOS 10). Then I clicked Delete. Although it showed No Messages, the bottom flag indicates "1 Unread" and Junk Email shows a notification badge of 1 in the folder tree.
Of course I know I can toggle Mail off, power cycle, turn it on and reset the counter but that is just a short term temp fix for me.
So I ask again, is this problem NOT returning for the rest of you?
Perhaps this is a problem with SMTP and Exchange type accounts? I have seen people throughout this thread specify they have Gmail or Exchange. Any others? I would like to try to isolate if it is an issue with the type of Mail account or is just simply a long standing BUG within the iOS Mail App.
Unfortunately, I may need to use Outlook or another mail application until this gets resolved. It is just too frustrating for someone who keeps their Email folders curated and likes to see a clean mailbox as a result.