It sounds like a timing/sync issue...

How are your feeds being routed before they come to the Catalyst, and what are they? Do you have a switcher sending auxes to you? If so it may be worth checking the cards on the crate, check they have timed outputs and not just monitor outputs.
Also is the glitching consistent across all your 8 inputs, as such a thing can be? Also do you have any Digital to Analogue converters in your system?

I know its more questions than answers, but quite often the issues arise upstream from the Catalyst.

cheers
Phil

Philip G Haynes
Live Visual Design and Direction