How does filtering of unsupported content work?

Unlike the free version, where check of the links availability ends simultaneously with the end of the crawl process (when 500 URL were found), in the paid version of the generator check proceeds to the last link, even if the crawl is already completed. This guarantees that redirects or dead links will not be included into Sitemap.
Although this is in agreement with the Sitemaps protocol and is not an error, the possible presence of links, for example, redirect can cause a redirect corresponding warnings in Google Webmaster Tools on the presence of non-direct links in the website map.