I have the same issue. If I edit a note on an iOS device (that I created on my Mac), I get a duplicate note(s). Im not sure what state Evernote on my Mac is at this time, but it's likely asleep. And most crucially, Im not using Evernote any differently to how Ive used it since 2009 - and Ive never had this duplicate note issue before. Im basically just using it across different devices, but for some reason that is triggering creation of duplicate notes.