Hello, I been experiencing similar issues just starting this week. I been using the new evernote web for more than a month and just last week the error "Note failed to update, there's been and error syncing your note, Please reload to resume editing". I reloaded at first, but got better results just by canceling the screen, my content depending on how fast I enter data could be all or reduced to the last inputs I made. I did tested just switching to the older version and the error disappeared.
Hope whatever was improved this week on the new version can be turned back so recuperate the usual functionality. In the mentime, even if it is annoying, if I need the highlight feature I will switch keep myself logged on the new one.
