A couple of DVDs I've had have had the CSS sectors go wild, continuously scanning until I quit the app.
The real pain ones are the X-Files S1 box set I am ripping to hard disk right now (I hope the other 8 series are not the same). At the moment I am working around by using Mack the DVD Ripper to an ISO and using makemkv on the ISO, but it is obviously much slower.
Anything I can do to collect info to help for the future?