it's likely the active ingredient (androsterone?) in small quantities
one of two causes are likely:
1) it dried on top of the skin before it could be absorbed - be sure to really spread it out over the largest area possible when applying - if there are "pools" of lotion, they're going to leave residue on top of the skin when it dries.
2) it crashed in the carrier - you may try giving the bottle a hot water bath to see if that helps get the material dissolved again...
if the material really is small like glitter, it's probably not that much material to really impact the efficacy of the product...it's likely just a few mg worth of material (low percentage).