Rekordbox 6.03 DVS failed after 1.5 hours first time of use

I have used Rekordbox 6 (now 6.03) many times at home and had no real problems, last night I used it for the first time at a paid gig, after approx 1.5 hours using exclusively vinyl DVS through a Traktor 10 interface the audio broke up digitally with no warning. Tried second deck and the same, stuttering and digitised noise. Checked DVS calibration signals from vinyl and both perfect.

Vinyl was controlling (start/stop etc) but audio output was awful and all over the place. With vinyl playing the visual waveforms were jumping around and stuttering.

Dell Latitude E7470 Core i7-6650U 2.2GHz, 16GB RAM, 2TB Intel SSD.

All drivers up to date including Audio 10. This was a pure software issue, the control signal into the software was fine and the waveforms showed it was an issue with Rekordbox being unable to stream the audio appropriately, not output hardware.

Thankfully had some real vinyl so could carry on but ruined the night and ruined the gig for me. Literally cost me money.

How do I fault find this? Do I have to play for an hour and a half or more to replicate it? Is there a log file? How can I trust Rekordbox 6 in a live environment now?

Chris.