Checked it on my end, and yeah, that’s exactly what’s happening.
KPDownloader won’t load un‑modified JSON files, so it can’t download anything unless the ‘Modify JSON’ option is enabled.
It’s a bit of a hassle, but here’s the workaround:
rename your existing scenarioForBeta folder to something else (just to keep the raw episodes from getting overwritten), turn on ‘Modify JSON’, and download everything again.
After that, delete the modified scenarios and rename your scenarioForBeta folder back to normal.
Just a reminder though: KPDownloader only supports the Unity player.
If you’re using anything else, there’s a good chance things won’t behave correctly.