VCI-100 sync turning off on its own

I'll just get right to it.

When I'm playing music with Traktor and I've got sync turned on with all four decks, or just two, or any combination in between, sync will just turn itself off on one of the active decks.

The button turns back yellow, and the sync icon on-screen turns off. This happens on both left and right decks. It seems to happen at random.

This is definitely not me bumping the jog wheels. I can be just sitting there watching traktor on my laptop, hands on my desktop's keyboard/mouse and I will see the MIDI signal LED flash and then sync turns off.

It doesn't seem to be sensitivity either. I can put my finger down on the jog wheel so it turns red, and then let go and sync won't turn off (I keep my sensitivity down a bit).

Any ideas? I'd say it's a hardware issue, but it's weird that it's just having this one specific effect.