AmethystProductivity, the problem is not a failure to sync, but note duplication... so really it's the sync process running amok, not failing to occur.
It happened for me this morning as well. I updated a note on the Windows app and soon had 4 copies of it, all showing the same "UPDATED" time, and 3 of them showing a "CREATED" date and time that is the same as the "UPDATED" time.
I certainly hope Evernote considers this problem a high priority. They'll lose a lot of customers if they don't fix it quickly (including me).