AutoMix deleting songs in queue

I am having trouble setting up DJAY Pro with my Pioneer DDJ-SX2. I am using it in two deck mode, on macOS Sierra (version 10.12). The only way I can get the Pre-Cueing to work is to set it to ch 3-4 under devices in preferences. So I have my main output to ch 1-2 and my pre-cue to ch 3-4. Everything works on my headphones now, but in automix mode if I fade manually to the next song, it removes the next song in the automix queue, and loads the next song after that in the list. So I lose a track each time, it doesn’t do this if I have the Pre-Cueing set to ch 1-2, but then my headphones don’t work.

So here is the flow of events:
Deck 1 playing = Song 1
Deck 2 paused waiting to play = song 2
Automix queue
Song 3
Song 4
Song 5
So I manually fade to deck 2, automix deletes song 3, and loads song 4 into deck 1