ONE OF THE TWO SUPPORT CYLINDERS FOR THE REAR HATCH ON OUR 2004 TOYOTA SIENNA FAILED IN FALL 2019, SO THE REAR HATCH WOULD NOT STAY UP. THE LIFTGATE SUPPORT CYLINDERS HAD PREVIOUSLY BEEN REPLACED BY TOYOTA UNDER RECALL. WE PURCHASED TWO NEW SUPPORT CYLINDERS, TOYOTA PART #68905-AE022'SUPPORT CYLINDER' FROM CAMELBACK TOYOTA IN PHOENIX, AZ, D/B/A TOYOTA PARTS FACTORY, BY MAIL, SHIPPED 11/19/19. I INSTALLED BOTH OF THE NEW SUPPORT CYLINDERS WITHIN A COUPLE OF WEEKS. NOTE THAT BOTH OF THE OLD SUPPORT CYLINDERS WERE REPLACED WITH NEW TOYOTA PARTS, NOT JUST THE ONE WHICH HAD FAILED. HOWEVER, WITH THE NEW SUPPORT CYLINDERS, WHEN THE WEATHER GETS COOL (BELOW 50 F) AND THE LIFTGATE IS OPENED USING THE ELECTRIC OPENER, THE LIFTGATE GETS PART WAY UP AND REVERSES, COMING DOWN UNEXPECTEDLY. THIS REPRESENTS A SAFETY HAZARD, AS THE DOOR CAN HIT SOMEONE STANDING BELOW IT. THIS IS EXACTLY THE BEHAVIOR FOR WHICH TOYOTA ISSUED THE RECALL ON THE SUPPORT CYLINDERS. THE UNEXPECTED REVERSING HAPPENS ON LEVEL GROUND WITH NORMAL USE OF THE LIFTGATE. IT STARTED HAPPENING SHORTLY AFTER THE NEW SUPPORT CYLINDERS WERE INSTALLED. TOYOTA CUSTOMER SERVICE TODAY TOLD ME THAT THEY WOULD NOT WARRANTY THE SUPPORT CYLINDERS, EVEN THOUGH THIS IS A SAFETY ISSUE. AS THE PROBLEM STARTED OCCURRING WHEN THE 2019 SUPPORT CYLINDERS WERE ESSENTIALLY NEW, THERE IS NO ASSURANCE THAT REPLACING THEM AGAIN WOULD SOLVE THE PROBLEM. IT APPEARS THAT TOYOTA IS SELLING REPLACEMENT SUPPORT CYLINDERS WHICH DO NOT MEET THE LIFT