Thanks Chris. The DAC and ADC chassis were both off, so perhaps that was the cause of the red DAC light (indicating bad "FIFO status"). I sent a sine to X1:SIQ-ESD, and got the correct sine from the expected channel -- with an additional -2.2 V offset that I also see on the other DAC channels.

I tried daqd stop --all / start --all, but it just took the ADC and DAC offline. And, the FE are now crashing every minute or so... maybe I started duplicate processes, if they didn't stop correctly. Rebooting cymac didn't help.