Hmm, interesting. Never seen this one before. You could try using a different renderer/video mode in the program to see whether that's a pure preview display issue. In order to do this, go into the program settings, e.g. by pressing "Y" on your keyboard, switch to the "Display options" tab and experiment with the different video modes to find out which one works best in conjunction with your graphics hardware/driver. It's worth a shot, but I don't really think that this is the issue here. More likely, this is something that is specific to the kind of source material you're using. Maybe you can do the following to work around the problem: Right after importing your footage, export it again into the MXV format via the export option in the "File" menu. After converting all the footage you need for your project into MXV, start a new project and work exclusively with the MXV material. If this is really a problem happening specifically with that source material, this approach should definitely get you around the problem.

I hope this helps.