Not a new idea...his original brain was destroyed during Morrison's run and...and...and...crap, it's been so long. I remember it was replaced, but I can't remember HOW. Something weird involving Dorothy, anyway. On the other hand, he was wholly mechanical for the rest of Morrison's run, and part of Pollack's. (ISTR his mind being stored on a floppy disk. For just such an occasion.)

I don't know if Pollack's run was restored with Morrison's (and presumably Arcudi's, since Fever's shown up...and...er...died), and if it's not, it's unclear just when Cliff was restored to...at least something resembling a brain. (Although if Arcudi's is in continuity, it becomes iffy without Pollack's.)