Oh man I figured it out. So I guess I applied a little too much heat while doing my heat shrinking on wires and it warped one of my dupont connectors. Replaced it and everything is work as it should.
Thanks so much for the help guys. Sorry it turned out to be something so stupid!
So the Duex didn't come with any additional twin ferrules, just single wire ones. The Duet Wifi came with two of them, but I already used them when I originally set up the duet. I tried taking them off and seeing if I could salvage them, but it's not going to work.
I ordered a ferrule kit the other day and it should be here today or tomorrow. It's only single wire ferrules though. So I have two questions.
A) Could I use a single wire ferrule and then attach a piggy back connector and have two wires going into it?
or
B) Could I use a larger gauge ferrule, say 10 or 12, and then a little electrical tape and heat shrink tubing?