Flashing sync and jog wheel controlling opposite deck! Help!!

Hey All, fairly new to my Xdj RX2 having just returned to Dj'ing.

Was prepping for a party this Saturday for which I'm taking the Xdj.  All was going well until I noticed I couldn't beat match the incoming track, any adjustments to the jog wheel were having no effect.

I took my headphones off to find that the adjustments I made to the right jog wheel were actually affecting the left (playing track).  It was almost like the wheels were trying to keep in perfect sync (even though the tracks weren't correctly beat matched). 

Sync button on the playing deck was on and flashing and would not turn off.  No combinations of button presses seemed to resolve the problem, making it absolutely impossible to mix!  They only way to clear this was to turn it off and back on - something I can not be doing mid-set this Saturday!!

Hoping I've turned something on by accident?  Any ideas?

Thanks - Dave