For some reason the touchscreen on my Surface 3 is acting up. At what appears to be random occurrences touches become translated as right-clicks and the only way I can resolve the issue is by restarting the tablet.
Another issue, potential related, is that the July 23 firmware update is not being installed. After some fiddling, I think the issue is that I was trying to install the update with the Type Cover not attached. I've forced installation of the update, with the Surface 3 plugged in and the Type Cover attached and it appears the system update is finally being installed.