Pre-cueing with multiple sound cards not working on Djay Pro for Mac

I have a problem with trying to use multiple audio interfaces for queuing. It appears to be a problem with Djay Pro on the mac and not the hardware as it works fine with Virtual DJ 8. It used to work ok but since I bought a Mixtrack Pro 3 it won’t let me do it. The integration in the programming seems to be a bit buggy as it works ok with Virtual DJ. When I try to select my Mbox2Mini as main out and the built in output for queuing the Pre-cueing box just returns to ‘none’. And after doing this when I try to use the two Mixtrack Pro 3 outs they stay on but pre-cueing is still not available. If I fiddle around for a while it seems to come back but I don’t know how or why.

I’ve found out some more about this problem. I can’t get the Mbox2 Mini audio interface to work alongside the internal output (to use with headphones) like I used to before but there is a way to get the two outputs of the Mixtrack Pro 3 to work.

When I first load it up the sound doesn’t work at all. But if I go to settings and select:
Main output: Built-in output
Pre-cueing: Split output
…the sound comes on…

Then I need to select (if I select Mixtrack Pro as pre-cueing here the pre cueing goes off)
Main output: Mixtrack Pro 3
Pre-cueing: Split output

Then if I select
Main output: Mixtrack Pro 3 (1+2)
Pre-cueing: Mixrack Pro 3 (3+4)
…the pre-cueing stays on and it works.

If I do this in any other order the pre-cueing doesn’t work at all using any devices. I still cannot get the Mbox2 Mini to work alongside any precueing device any more and would like to know why.

It is frustrating because I need to go through this process every time I load up Djay Pro for it to work at all.