append option bug?

[shs2002]

Hi!
I am using sselph scraper on windows 10 PC for Emulationstation windows version by jrassa.
It is great scraper. But, I found a strange happening on its append option.
If I use append option is true, it is not skip existed rom DB in gamelist file. It is add same rom DB in gamelist file.
This issue makes me very tired for management rom DB on gamelist file.