I keep passwords in a file I use mainly on my iPhone. I noticed at the end of my file was a box or a banner saying "conflicting modification on Date..."
At first is was one dupe and was only a problem when searching because I put passwords at the end of the file and the search picked up the first, not the most recent.
I started putting passwords at the top instead and forgot about it. I looked ate the note online where I could see it better and there are tons of these duplications.
NOTE: the TEXT in my note is duplicating inside the same file, not making duplicate NOTES.