OVERVIEW
the task used by creativecore (and other mods) is archived and had missing the capability of set "side versioning"
this is important and helps users to rid off bloat mods from server when only had funtionality on client-side (like AmbientSounds)

SOLUTION
Replace CurseGradle with CurseForgeGradle (by Darkhax)
implementation on the upload task is basically the same so it can work without break the buildscript, and it can contain the side version mainFile.addGameVersion(mcversion, "server", "client")

and doesn't require the patch on the old task when the CF key is null

Finally did it. Thanks for suggesting this.