Greasy Fork

Changing line 245 to this seems to fix the issue:

formats[format] = [track.ttDownloadables[format].urls.map(cdn => cdn.url), EXTENSIONS[format]];

I successfully downloaded several episodes individually and a series as a batch after making that change

Still not working.

sigh, I should've read your post earlier. 20 minutes earlier... :D It should be fixed in 4.2.1. I tried to future proof it a bit (just show an error message instead of failing silently) while keeping it backwards compatible.