I had the same problem, Nikola responded with this:
As described in other threads on this forum, there are two ways to set the clock.
– The recommended one (see page 12 of the M-Dante guide) is to set the GLD Audio Sync to Internal, and the Dante card to Preferred Master and Slave to Ext in Dante Controller. This makes use of the GLD clock.
– The alternative method is to set the GLD to Sync from I/O Port, and no option ticked in Dante Controller for the Dante card. This makes use of the VCO on the Dante card.
Either method should work reliably.