What it says on the tin. It appears that with the latest steam workshop update, functionality between Gaslamp's mod loader/publisher and the workshop is now FUBAR. Mods updated/published after the update do not show up in the mod loader or publisher. Subscribing to this workshop item will have no effect, as I belatedly discovered after attempting to update the previous version of RR, going so far as to scrub the mod off the workshop and upload again. Mods uploaded before the workshop update are fine and recognised, but anything updated/uploaded after the change is not listed in the loader/publisher.
Hmm. I can't really reproduce this on my side. What I did was try to publish an already functioning mod and see if it would let me subscribe to it, which it does just fine. Is there a specific thing you have trouble with? If you want, PM me your mod, I can see if it will let me publish on my side (I'll delete it after, of course)
No worries. It appears that the problem was not on your side, I just got off steam support and they appear to have fixed it now. A boo boo with the steam workshop system upgrade. Sorry for all the fuss, I got a little overexcited and OCD-ish.