Stylus Buildup?

Lint. The air is littered with it. Using a stylus brush?

To Newbee's question I would add are you doing a destat of some type before you play? And are you using a brush as well? I think that the reason some records have or produce more than others is due to the amount of static charge in the album. Or at least that has been my theory. Could be right could be wrong.

Wax. Some cleaners dry up the pressing release agent, but do not remove it. So it is a dry, ultra thin layer of waxy (invisible until scraped) white stuff uniform on the surface. Your needle scrapes it off. It is no big deal. Change cleaning fluids if you want to stop having it.
If not, it is NOT hurting anything
It is sort of like dandruff. Some LPs will have it, some will not.