Many of the threats on CARCOSA appear to be extra-terrestrial in nature: Space Aliens, the God of the Primal Void, perhaps the Old Ones. This invites speculation that other stars and planets are quite nearby.
Stars in the Hyades are 'more enriched in heavy elements' than our own sun. What might this mean in game terms?
It mentions that clusters suffer from 'evaporation' or 'dissipation' in which member stars continually drift/are pulled away. I prefer to think that the Carcosan Hyades are actually drawing together, continuously capturing additional stars within its malign embrace.
In such a crowded neighborhood, the 'stars being right' might be a more frequent occurrence. The Hyades also have lots of binaries - maybe CARCOSA has a companion that appears infrequently?