Water Pump problems of the 2018 Volkswagen Tiguan

Driving at 42-45 mph on a 0% slope. Car initially maintaining about 1,300 rpm. Without changing speed, pressure on the accelerator, or incline of the road, transmission would shift down by 3-4 gears resulting in a jump in the rpm up to about 3,200. Vehicle would cycle through the down shifting and the jump in rpm, and then shifting back up to lower the rpm back to normal. Within 1. 2 miles, car cycled through this three times, and that was what I could capture on video! it continued for 15-20 miles before I could get it to a Volkswagen dealership. Finally, the engine temperature gauge shot up and sat about maximum value for about 3 seconds and then fell back down to dead center (normal operating temp). At that point, I was already on my way to vw to drop it off. About 1 mile from the dealership, I got the "check coolant! see owner's manual. " alert on my dash even though the temp gauge was normal at that time. Finally got to vw and was told the transmission thing was normal ("they like to hunt a lot"). I don't believe that for a second. After 18,000 miles, I would not all of the sudden realize the transmission doing that. Shifting by one or two gears is probably normal for a dsg, and I'm sure that has been happening all along - but it is so small that I don't notice the change. When a car shift down by 4 gears within 1-2 seconds and the car lunges forward as the rpm shoot up to maintain the speed, that is something that isn't normal. Currently vehicle is still in the shop. Will likely need a new water pump, coolant reservoir, wire harness (due to coolant migration). They also think there may be transmission fluid inside the coolant reservoir, but are still trying to tell me that the shifting problem is "normal". . . I'm tired of dealing with Volkswagen and their shifty service department and procedures and can't wait to get rid of this car.