"Aliens" from my Alien Legacy boxset is showing all the symptoms. Very bad pixelation, skipping, audio out-of-synch, freezing etc. All after the layer change. In fact, everything BUT the "coffee stain".
To make it worse, this is the first time I've tried to watch this title. "Alien" was fine. I'm about to watch "Alien^3".
I'm sending a polite but angry letter to the makers of the DVD and a "please can I have my money back" letter to K-Mart Online.