Apparently, adding -- in a jar's filename on CurseForge screws things up, and even Maven Helper utilities (like those by Wyn-Price and Darkhax) can't figure out the CurseForge maven URL for such files. No one I asked at Forge knew what the URL is for such files either.

The simple fix is to just refrain from using -- in the filenames of future releases.

Will be fixed with the next version :)