This is exactly the behavior I'm seeing. While I'm in the middle of typing, Evernote flickers and I end up with a handful of duplicates (each with various chunks of what I've been typing). I first noticed this around early January of this year.
As to the questions asked earlier in the thread:
>Multiple browser tabs were open with the note being edited
No.
>Your Mac or Windows Evernote client was open with the note being edited
No.
>Other people were looking at the note the same time you did because it was shared
No.
>You lost internet connection while editing
No.
I'm running Evernote web in Firefox 44 on Ubuntu 15.10.
