Starter cranks when key is in "run"

I'm really hoping someone has an idea of what the heck is happening.

I had the starter go out on my 2012 Enclave so I replaced it with a new OEM part. Now when I turn the key, the starter starts cranking when I get to the "run" position. Going all the way to "start" doesn't cause anything different to happen, it just keeps cranking away.

I thought it might be the ignition switch so I replaced that...same thing. I've tried swapping the starter relay and rear defrost relay since they're identical, but no dice. I'm pretty much at a loss at this point.

Does anyone have any ideas as to what I should check/test?

Almost forgot...I tried using the remote start as well, but it cranked for about 3 seconds and quit.