Indeed, the flashes appear as a full white flash that covers the entire screen. I've also noticed (although this could just be my mind playing tricks on me as it can be tough to spot) that the scene will often darken just slightly a second or so before the flash occurs. This isn't something that's visible most of the time though, but it's enough that I can sometimes predict a flash.

You said these were on "all media and channels" does that mean you're getting the problem when connecting devices with non-component inputs?

If you haven't checked please try running your DVD player through the composite inputs and checking to see if it's still an issue. That was what I found to be the most perplexing part of this. If it was just adding noise to the signal or amplifying underlying problems with the disc I could understand, but transfering a component signal from a component input to a component output should (I believe) cause less problems than upconverting a composite signal and passing it out through component.