This issue also came up for me a few weeks back in the Evernote client on OSX.
10.24.3-mac-ddl-public (3041)
Editor: v134.0.17043
Service: v1.41.4
This seems like a major problem and is cluttering my system with so much junk. Some notes are randomly duplicated just once, others not at all, and some 5+ times. I've relied on Evernote for many years and this is the first time I've ever had a significant issue. Can someone from the Evernote team suggest any workarounds?