Using "History" folder complicates your explanation, KOReader has a History that holds your recently opened files listed, with the most recent at the top. This is separate from any "History" folder you may have in your file structure.
I seem to remember this issue, or a very similar one, discussed at the project on
Github. I don't remember how it turned out, or the issue number, but if you find it you can add your concerns. Or you could open a new issue.
Luck;
Ken