iCloud mail keeps moving back to Junk folder after been marked Not Junk

[ztirffritz]

What email service are you using? For something like Gmail or Yahoo It could be that the provider has server side filtering that is moving things before the Mail app even gets it. Every time you move it the server re-evaluates it and moves it back. Sometimes you have to use the web interface for a bit and turn off or 'train' the filter on the server to know what is junk mail.