Calling them "seasons" sounds like a misnomer. (no offense)
Masquerade was a Kajishima story for certain, but my understanding has been that he wasn't involved in the shoddy follow-up to it. That was
Zoku Gosenzo San'e.
However, when I looked for something to back that up, the only site I found at a glance say that was
this review from 2003. So take that for what it's worth.
I even looked up an episode for it just now, but the credits themselves were neither Romanized nor subtitled, soo....
That "third" season was called
Anata dake Konban wa, and was 100% a Kajishima project. While it had crossover characters and (if I am remembering right) some connection plotwise to
Masquerade, it was mainly not the same story. Really only Beth shows up. (And an unrelated masochist Kuramitsu expy, but I mean this is Kajishime we're talking about....)