shadows of mordor goty appears in giveawyas i can join, though i already own it

Hello, this is something i dont understand, i already own the games with all dlcs(i bought it on bundle stars) and yet, despite having used the sync function a lot of times in the last months and even today, it does appear as a game i can join. I wont obviously, but i was wondering why. The edition i got was clearly named goty edition, and i own all of the dlcs sold on the steam store.