I finally got a chance to see the promised Cardcaptor Sakura OVA. Naturally as a devoted fan of the original series I had to watch it and nit-pick.
The OVA actually turned out to be a bit of a letdown since it is just a remake of the final episode of the original anime series, but with some minor differences. (Most of the differences involve who gives what to whom and where.) Though the differences may seem unimportant they have some consequences. For one thing they pretty much establish that the Sealed Card movie cannot be canon.
I figured out the source of the differences. The OVA is based on the ending of the original manga. It follows the manga almost page by page (omitting some minor scenes which still may not comply with Japanese broadcast standards.)
This has consequences for the Cardcaptor Sakura Clear Card Chapter anime which has been promised for next year. It is going to be a sequel to the original manga, not the original anime series. This is a bit odd. Usually when they make a sequel to an anime series they try to keep it consistent with the original, even if the manga has diverged.
However the original manga and anime were so similar that the only viewers likely to notice an issue are those who watch the original series and then watch the new series right away. If you do that, expect to see continuity problems.