One thing you may want to try is turning off automatic brightness. If you go to the Settings charm by swiping from the right side of your screen, going to Settings\Change PC Settings (at the very bottom). Then when the Settings app loads, go to PC and Devices\Power and Sleep and uncheck the first check box that says to automatically change your brightness. This will make it so that the display will stay fixed at your preference and not automatically change. Like the iPhone, it can sometimes feel overly aggressive, especially when you are in dim light or use a particularly high brightness setting. Hope that helps and glad you like your Surface. If you think it is a hardware problem, please do use Microsoft support or the Microsoft Store!
I have auto brightness off. This is not the issue. I have filmed it and will upload it to YouTube so you can see it. This is my second surface, I had it replaced yesterday and the new one does it as did the 4 demo ones the retailer had in store. Today I went to a different store and all 3 of their demo surface 2 and pro 2 do it too so it's not just me nor is it just a faulty device. Unless the entire surface line has a serious design flaw.
Now my new one has another fault. The display wont wake up when I want to use it, I have to do a hard power down and turn back on to get it on again. I'm not impressed anymore.