I'm also watching HD on Expressvu and I saw it during Alias, a green rectangle in the top left corner of the screen. It was especially visible during darker scenes, of which there were many. A similar green blob also plagued ABC's Once and Again a couple of weeks ago.
So far, I've only noticed the problem during ABC's dramas, not on its sitcoms or movie presentations, nor on any of the CBS programming.
So far, I've only noticed the problem during ABC's dramas, not on its sitcoms or movie presentations, nor on any of the CBS programming.