No Output From CH3

I already submitted a support ticket, but after reading it takes a while to get a response, I thought I'd see if anyone here could offer some advice.

I recently picked up an iCA4+ for integration into my guitar pedal board. I have a Line 6 XL Live, as well as a Looptimus midi controller I'm integrating this with. I use a PRS Hollowbody with a piezo as well.

So I've run the magnetic pickup outputs to the XT Live, and from the XT Live out into the analog inputs 3 and 4 of the iCA4+. Then I also ran the piezo signal from the guitar direct to analog input 2 of the iCA4+.

I have the Looptimus plugged into the host port, and an iPad into one of the device ports. The other device port is plugged into a PC right now, but just temporarily while I get iConfig all setup.

So I want to mix the XT Live signal, and the piezo signal, to output on the analog 3 and 4 output channels of the iCA4+, and have multi outs from the iPad going to outputs 1 and 2.

When I do this, CH 3 doesn't get any sound. In the patch bay, or in the audio mixer screen, no matter what I choose to output on CH3, I get nothing. The meters are bouncing to show it is sending audio, not no actual signal is heard.

I am getting sound from all the other channels. This makes me think I have a hardware issue and probably need to send it back to Amazon, where I bought it, but thought I'd check 1st; in case there's something special with CH3 I am missing.