White powder around the diff?

H,
After one or two runs of my brushless buggy, I found there was very fine white powder around large end cap and motor mound. It looked like a very thin coating of white paint.
Did it come from the slipper pad because of friction or it was just some unknown dust?
Dose this situation imply that it is too much slip for the pads?
The weather was cold out there. The temp of large end cap was just warm.