Is it possible that you have your master fader assigned to the DCA? That would explain not getting any audio from other channels when the DCA is down, even without those channels being assigned to the DCA.
Identify the channel DCA mute LEDs on the channels, they’re the small red LEDs near the main mute button for the channel. When you mute the DCA, the DCA mute light, the big one on the DCA fader, should turn on (white > red), you should also see the DCA mute LED (small red ones) for the channels turn on on any channels that are assigned to the DCA. Are you getting DCA mute lights on any channels other than your choir mics?
Chris