Up Arrow Key Shows Application Windows (without having set it up as a shortcut)

I'm using OS X Yosemite 10.10.1 and whenever I press my up arrow key, mission control will display the application windows while also performing whatever action the up key is expected to (e.g. move the cursor up in a text field). I checked the mission control and keyboard preferences and made sure that the up key wasn't mapped to any shortcut. When I found that there was no problem there, I tried unchecking the "application windows" shortcut in System Preferences > Keyboard > Shortcuts > Mission Control then tried pressing the up key and it played the alert sound and still performed the expected action. Then I went to System Preferences > Mission Control and found that there's no way to even map the up key to a shortcut there. So I'm really confused as to where this shortcut is set and it is a really annoying problem, anybody know where how this could be happening despite not being set in System Preferences? Is this simply a bug that has been/will be resolved in an update (it seems like too major of a problem to make its way into a release though)?