My Tech lead is concerned that his use of a script to generate XML sitemaps for some client sites may be causing negative issues for those sites.
His concern centers around the fact that the script generates a sitemap which indicates that every URL page in the site was last modified at the exact same date and time. I have never heard anything to indicate that this might be a problem, but I do know that the sitemaps I generate for other client sites can choose server response or not.
What is the best way to generate the sitemap? Last mod from actual time modified, or all set at one date and time?