Old nonexistent page on a site with ads -> 301 redirect to a new page on a site without ads Results in the original site being taken out of rotation, even though all pages have ads.
Not a bug, it's a feature. You'll have to get the old page out of the Google index. (Exlcusion request for instance.)
If you'd 301 10K no-longer-existing but still-in-the-index pages to the homepage you would get credit for those. With this feature you don't. Up to you whether you want to validate or not.