I’m not sure I understand your description, but it may be a result of the HDV format. HDV is a form of Mpeg-2 which has dependency between frames. Thus a problem with one frame can affect several following frames rather than just that one. This might be what you’re seeing.
Try capturing a short HDV clip as Prores and see if it looks better. If you post a short clip, it might be easier for folks to give you feedback.
John
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