Strange playback issue

I just noticed an issue on playback of both BluRay and DVD's burned off timeline. Original source footage is HDV, imported using HDVSplit, and edited w/ Vegas Movie Studio HD Platinum 10.0. This issue is present whether viewing playback of disc on a computer screen, or an LCD TV screen.

Looking closely, I've noted an instability to the image that occurs exactly once each second. There is a slight shift in sharpness that is visible, looking almost like some form of interference that occurs exactly once each second. I played back the native HDV file that I captured on the computer (before editing), and this artifact is not present at that point. Just a steady, rock-solid image. I only find it on playback of a DVD or Bluray disc.

When I burn the disc, I've pretty much chosen the default templates for HDV. I tried changing the field order from upper field first to "lower field first" setting, with no success. Also selected "reduce interlace flicker," nothing. Rendered at 1080P, nada.

I'm a newbie, have searched forums but not found anything. Can anyone help? Thanks.