Here's the lowdon:

I had set up a SVCD profile to record a movie. The bitrate I planned on using was pretty low, so I tested it out by capturing somethingusing the encode interlaced option and then capturing it but this, time de-interlacing it so I could check it better on my PC. The bitrate was OK. This is a normal everyday thing I do before capturing, the only difference was that this time I had set the profile to deinterlace.

The problem:

I set the profile back to capture interlaced and captured the movie. I played it back on my PC, and to my horror it was de-interlaced, with the audio out of sync in places.

Is it just another bug with MMC 8.1? As I said, the only thing I did differently was a test capture with de-interlacing before I changed it back to interlaced.