A vapor compression system (20; 400; 420) comprises: a compressor (22) having a suction port (40) and a discharge port (42); a heat rejection heat exchanger (58) coupled to the discharge port to receive compressed refrigerant; a heat absorption heat exchanger (88); a first lubricant flowpath (120, 126) from the heat rejection heat exchanger to the compressor; a second lubricant flowpath (121, 126) from the heat absorption heat exchanger to the compressor; at least one lubricant pump (190); and a controller (900) configured to control lubricant flow along the first lubricant flowpath and the second lubricant flowpath based on a sensed fluctuation.