Since the patch today seems like the mouse buttons M4 and M5 are no longer supported on my logitech mx100 mouse. It was working fine yesterday, and still work today on all other programs besides FF14. Seems like this isn't an issue with all mice though.

In case someone else has this issue and wants a bandaid fix: Use your mouse's settings or a program like autohotkey to bind it to some keystroke, then in game keybind whatever you want your mouse button for with that keystroke. You also have to relog because (another bug) the game won't register the change.