Output 3 volume level drop

CorOS Version: 1.4.1

Describe your issue:

The output volume level at Output 3 has suddenly become much quieter than any of the other outputs. For example, it is perhaps only 10% the volume of Output 4.

Steps to reproduce your issue:

I expected this to happen:
When I connect Outputs 1, 2 or 4 the volume levels are much louder/ higher.

I have tried the following things:

  1. have tried setting all levels to unity on the I/O screen.
  2. I have checked I am running the latest CorOS version (1.4.1)
  3. I have unplugged all connections including the power and waited 20 minutes before restarting.
  4. I have rebooted the device.
  5. I have carried out a factory reset.