Oh that may be a different ball game. Not sure about the ins and outs of carbon grease but at work we use a special 'grease' (think its gritted or something) but thats for seatposts so you dont have to over torque the seatclamp i guess.
Maybe some chemicals in some greases could react with the epoxy used for the carbon?
Maybe i have no idea what im talking about?
Is it bb30?
I have done a couple bb30's and just used standard grease. This is only in the past few months though so cant judge long term effects.