[Lombra]

To FauxScrollFrame_OnVerticalScroll you should pass your update function, not its return value. (which is nil)

FauxScrollFrame_OnVerticalScroll(self, offset, BUTTON_HEIGHT, RemGank_ListFrame_Update(self))

becomes

FauxScrollFrame_OnVerticalScroll(self, offset, BUTTON_HEIGHT, RemGank_ListFrame_Update)