Man, I have this issue too. Between this and other issues, they are really piling up and making me question why I spent so much money on this device if the QA is absolutely terrible. I had the very first Surface Pro, and it too was riddled with random issues like this (using the trackpad while charging caused it to go haywire, had to ground it by touching the tablet with my other hand...). I had hoped that since this is the 7th iteration of this thing, most of the kinks would have been fixed. I love this form factor, but damn, Microsoft can't seem to make a stable product.
I've got until May 14th to return it, and I think this issue will be the straw that breaks the camels back if it isn't fixed by then.