No, I didn't change anything. I opened the game with 1080 and never moved the scene. Left the game and unplugged 1080 and plugged in 1440 and went back in game. It's the only game installed, so I can't try it on another game.
I have 3 display ports on the card in my old system. I assumed they were for triple monitors. Does it matter what port I plug in to?