I was simply typing in a note for approximately 2 hours. When I was done editing it, I could see that 3 duplicate notes got created automatically. Each of the duplicate notes was created at different times. For example if I wanted to write 100 lines in my note. When I was done, I would see multiple notes created with the same file name automatically - one with all 100 sentences, 2nd with 70 sentences, 3rd with 50 sentences, etc.. I never created any "duplicate copy" of any note 'manually' myself deliberately.
I am afraid this unpredictability in Evernote should not delete my precious note(s) altogether someday! Please have a look at the timestamps of all the notes (encircled in red) in the attached screenshot and suggest.