Y'all,
I believe I know what caused my problems with Evernote saving multiple versions last winter. A few months later my desktop computer was struggling with frequent disconnection to WiFi. After a month or more it occurred to me the problem might be with the WiFi radio on my computer and not with my WiFi router, so I purchased a third node for my WiFi mesh network, connected my desktop directly to that router via Ethernet cable and turned off the WiFi on my desktop. Connection issue is no longer a problem.
I suspect the difficulty I was having with Evernote last winter was the earliest symptom of my computer's failing WiFi radio . Evernote software may be more sensitive to dropping connection to the Internet bc it's designed to save notes locally whenever Internet service isn't available. My solution may not apply to other's situation. As said above, there are multiple causes of duplication of notes.
Responding to Gazumped and some of others in this thread.
I do not want to break my notes into shorter notes and later combine. My notes don't tend to be long, especially in one sitting. The day I need to start using another app for typing my notes during a meeting as a first step before pasting into Evernote is the day I dump Evernote. Notes taken during meetings is the number one reason I purchased and continue to use Evernote; it needs to keep up with my not very fast typing.
I'm going to try an experiment next time I'm taking notes where I've got a poor connection to the Internet by turning off the WiFi radio on my 5th Gen iPad. I want to see if the Evernote app stops lagging when I take away the need to save my note anyplace but my local device. This should also stop creation of multiple versions of my note.