thanks! I was able to replicate the sitemap.ashx problem on my local machine and fix it so it will be fixed in the next release. In the meantime a workaround is to uncheck the "Include in Search Engine Site Map" under the SEO tab in page settings.
I got to the bottom of the page modified issue as well.
basically page settings has 2 properties:
LastModifiedUtc //this is the last time a content feature on a page updated the time stamp
LastModUtc // last time page settings saved
what is shown in the page settings page is the latter, what is shown in the sitemap.ashx is the former