No Signal from ADAT or SPDIF Out

I can’t seem to get audio pumped out of my new MR816CSX digitally. It can RECEIVE signals from the ADAT / SPID cables (either the ADAT optical cable or the SPDIF cable) but I always get silence on the other DAW when sending anything OUT either cable.

ADAT is set to ADAT Optical, unit is not in external FX mode.

Interestingly, it DID output sound - albeit highly distorted sound - when I accidentally had the receiving DAW at a difference sample rate. But when they’re the same sample rate (as they should be), I get nothing. Cubase does show that I am outputing audio on ADAT 1-2 (the meters show activity, anyway).

I’m pretty sure at this point the unit is defective and I’m about to RMA it, but I figured I’d check here first. Any thoughts?