Now that I figured this out, its a really cool feature but for the last week and half its been a real pain.
At some point (likely when locking the computer and wiping the keyboard) pressing home and end keys on my Surface Pro stopped working as expected, to the point I put in a request at work to get it replaced.
Turns out as I described the behavior and noticing it was doing the opposite function behavior, the tech asked if all of the function keys were doing this and lo and behold they were. It was until I realized the whole row of keys were affected that I was able to register that my problem was that the FN key was locked in some manner.
One quick Bing search later and I found this page - http://www.surfaceproblog.com/trick-lock-the-fn-key/
Press “Fn” + “Caps” keys simultaneously to set the lock and remove the lock. Easy enough, the interesting thing is there was no tool tip announcing the change in behavior.
Make it a great one!