@Mel
The network hardware initialises on boot, so it’s not a software switch, though I couldn’t say that software/firmware isn’t related to what you’re seeing.
I’d recommend storing a copy of your show, then carrying out a firmware reinstallation via USB using a fresh copy of the latest firmware from the resources section of our site here – https://www.allen-heath.com/hardware/cq/cq-18t/resources/
Then perform a full factory reset by holding down HOME and SoftKey#1 when powering on.
Test the network in this state before reloading your show to rule out any software/firmware/data involvement.
If you’re still having issues, or if this points to something related to your show data, please contact us through support.allen-heath.com so we can investigate this further.
Thanks,
Keith.