No sound for 30 seconds XDJ-R1

I have an XDJ-R1 which has a strange problem. After powering it on and selecting the MIDI/PC source button, there seems to be a 30 second delay before sound comes out of master out.

If I turn volume of speakers up loud I can hear something faint, then after 30 seconds the sound comes blasting out.

Knowing the sound is temporarily muted, I have to wait until the sound comes on to adjust my monitors volume. Its not the end of the world but is very annoying and if someone else were to power the system up they might blow out my monitors.

I have had the XDJ-R1 for several years and it never behaved this way until recently(6 months ish).

Set up with a mac pro on high sierra.