Transcoding and A/V synch issue

Has anyone heard of this? I get a/v synch errors when burning a DVD. I inspected the VOB files and found that the audio and video would be fine for the first 2 Gb or so and then the video would suddenly “backtrack” and repeat the last 15 minutes or so of video while the audio kept playing normally.

If you’ve encountered this let me know how you solved it. It happens with regularity with my DVD compliant mpeg 2 files VBR but not when it is CBR.