While this sounds like a hardware fault it seems to be behaving like a software bug. It’s registering on the output meters in the IO settings, both in Cortex Control and on the QC itself. Changing the output to other outputs works fine (in the Cortex Control), and sometimes changing back to output 3 kickstarts it, but not reliably. I’m mega hopeful this isn’t a scenario where I have to return the device as I use it daily. Any advice or users experiencing the same issue?
It occurred to me that I use output 4 to drive a power amp for my guitar and the main large volume control assigned to 3-4 as a quick way to adjust the master volume. After much faffing with leads and adjusting I got sound sometimes but not consistently. It could be the relationship between the volume control and the connection. Unfortunately it’s all in a rack and vey challenging to plug and unplug and swap leads. It still seems to be 3 that has inconsistent behaviour compared to 4.
Update, changing the output at the end of the lane from 3 to 3&4 made both outputs work. I definitely think the silent 3 thing is a software bug.