That’s normal, as the bridge is doing only the first unfold. More on this here:
As for MSB, they write in the specification that they implement the full decoder, so Audirvana should be set to MQA decoder in order to pass to the DAC the bit-perfect stream for unfolding.
Disable MQA autodetect and try again. Make sure it’s still set to MQA decoder. Also make sure software volume control is disabled and no plug-ins are doing any processing on the signal.
If it still doesn’t work, you’ll need to contact MSB.
Or even better, realize that MQA is NOT a Hires format. MQA is in fact a 17 bit 48 kHz lossy format that is upsampled to what ever is embedded in the file.