Young Thug's now facing a felony drug charge, and a misdemeanor for tinted windows ... TMZ has learned.

The rapper was arrested Saturday in Georgia by Brookhaven PD, and booked on one count of marijuana possession. He was also slapped with a charge for having tinted front windows.

Thug's had a year full of legal issues, but so far it's worked out for him -- he skated on another felony drug charge in April thanks to a technicality, and was cleared for allegedly slapping a woman outside a nightclub.

Third time's a charm?