One of my Dante devices has a percentage value shown against its Clock Status – why is this?

This is because the device has been configured with sample rate pull-up/down, and so is operating on a dedicated clock domain. To check if a device has been configured with sample rate pull-up/down, open the Device View for the device, and select the Device Config tab. The sample rate pull-up/down setting is shown in the Sample Rate section.More info