XDJ-RX Volume fluctuates?!?!

Hello Everyone, 

I just noticed something while djing last weekend. Randomly whilst djing the volume from both channels with fluctuate up and down. If I then pressed down with some pressure anywhere on the decks, the volume would change back to normal.

Never experienced this before. It was a bit awkward because when the voume would go low, I would bring the gain up and then randomly the volume would blast back up to normal volume.

Has anyone experienced this?

Thanks

Jesta