Archived Messages Reappear in the Mail App Inbox I'm using Gmail on my iPhone 6 (IOS 9.1). When I archive some messages (by swiping left on the message in the Mail.app), they disappear from my Inbox, then get added right back a second or two later. This has been going on since IOS 8.1 and still isn't working right since upgrading to IOS 9.1 I figured it would have been fixed, but it's not.

I tried archiving to different folder than All Mail but that didn't solve the problem. Also, there is no pattern to the messages. This is happening regardless of who the message is from or its content.

I gave up after a year of dealing with this annoyance and using Outlook for now, but I'd really like to use the Mail App on my iPhone again.

Does anyone know how to fix this?

One other possibly related and interesting note, the mail app in OS X also does the same thing (click the archive button, message disappears for a few moments then pops back in the inbox, then disappears again). Perhaps IMAP commands are being queued up, then mail refreshes and notices the message hasn't been actually moved yet, and adds it back to inbox... just my theory.
This could be an issue with your iPhone settings.

Go to settings > mail, contact, calendar > Gmail

Here you will see you gmail account, select it.
On the following view, there is an option for advanced settings.

Here you can change to with folder archived mails should be placed.

Please let me know if this solved your problem.