If you're able to toggle vinyl mode and the problem persists, the likely culprits are:
- the DDJ not getting adequate power over USB (try a different USB port, or cable, perhaps even a different computer)
- static interference (try disconnecting outboard audio devices such as speakers, mic, etc, or if you have a laptop, try unplugging the charging cable to see if that helps)
- grounding (see above)
Let us know if anything there helps.