We have noticed from 1st of August that Google set some new validator for submitted video sitemaps.
It doesn't concern our sitemap generator or other generator (if was working properly).

The problem is that video sitemap will remain as not valid in Google Webmaster Tools due to duplicated video titles or descriptions.
We do not know how this can affecct video search engine results, anyway this is case of each individual webmaster - to take care about his videos, about avoiding video titles and descriptions duplicates.

D.

It's true. I noticed since monday, none of the new videos posted to my site, were appearing in Google search results.
So I changed the names or removed the duplicate videos, and now my video sitemap is working ok again.