We are aware of an issue resulting in an audio dropout, followed by large latency - that can be reproduced by toggling the WiFi from off to on while Serato DJ hardware is connected and playing audio through Serato DJ.
At this point, we believe this is limited to RANE hardware, and only affects OS X 10.11 El Capitan, and macOS 10.12 Sierra.
The only work-around (once the issue has been experienced), is to reconnect the hardware. Resetting the audio buffer under SETUP --> AUDIO, will not resolve the issue.
The issue has been reproduced using other audio software, so we believe the issue is not specific to Serato DJ.
We strongly recommend you either disable WiFi before launching Serato DJ, or refrain from toggling WiFi off then on again, if you are using a network connection during use of Serato DJ.