Hi Silverskates. Blind Internet diagnosis is a very difficult, so I will make this suggestion (only thoughts on possible scenarios): The rain sensing sensitivity is adjustable. By using the dial on the wiper stalk, you an adjust that rain sensitivity. And you may need to do this at higher speeds.
So try adjusting the sensitivity, if you have not already done so.
Also, we need to keep in mind that the frequency of wiping is solely determined by a sensor located under the rear view mirror. So if there is rain/moisture in front of the sensor, it will wipe, even if the rest of the windshield may seem to be relatively rain free.
As an example: Let's say a freak/large rain drop hits right dead center in front of that sensor, but not much rain is hitting the rest of the windshield, the sensor will set off a wipe, while we may not see much rain on the windshield in front of us.
And vice-a-versa...There could be rain on the rest of the windshield, but not much in front of the sensor for some god-forsaken reason.
If the above thoughts don't seem to apply to your vehicle, here is a suggestion: See if you can duplicate the issue at home using a hose and spray nozzle. If you can, then perform the same test at the Dealership, in order to demonstrate to them that your wipers are not "working as designed". They certainly must have a hose there. And bring your spray nozzle from home, so you can duplicate the test as closely as possible.
Again, these are all just blind Internet thoughts and suggestions.
EDIT- Oh...and you may get more replies relating to your wiper issue if you begin a new thread with a more relatable title than the OP's "Side Mirror Tilt in Reverse". Maybe "Rain sensing wiper issue"?
I am sure others will have more advice and suggestions, so keep us updated and good luck.