Sounds like a brief SPIKE in the Bitrate, that although MAY seem OK in Preview, but really shows itself in a final burn. I never take for granted a Preview, I ALWAYS do several DVD-RW Q&As via a standard STB to get to a draft final.
A] Download Bitrate Viewer: Bitrate Viewer 2.3 - VideoHelp.com Downloads
B] Always be prepared to analyse your output, I do!
Relying by getting it Q&A-ed on a neighbour's STB could be a false positive, in as much as you don't know what you've got.
I write this stuff 'cos I don;t want you or others to waste their time fiddling at the edges of a problem, when what you've got it is a far more fundamental issue going on AND your left with an unknowing, simplistic appreciation of the issues.
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