I've been battling Google Webmaster for the last month in an attempt to get rid of all Schema.org errors. I've been stuck between 2-3 errors for the last few weeks. Every time an error is fixed and Google indexes it, it inevitably pulls up another error from a page that was indexed 4+ months ago.
An error just showed up today that was last detected in February of 2015.
All three of the pages that I'm currently getting errors for no longer exist and have been 301 redirected to pages that do not have any Schema.org errors.
My process for removing the errors
Redirect the page and wait a couple days for Google to index the changes.
If nothing changes, I give Google a nudge and have it fetch the page with the error.
If nothing changes, I request to have the URL removed.
Other things I've done
Every few days I have also been having Google crawl and index my entire site.
An updated sitemap has been submitted over a month ago.
Google will eventually stop showing the error but I am not exaggerating when I say that I have been dealing with 2-3 errors on roughly 10 different pages for the last few weeks. Every time a page with an error is removed from Webmaster, a new one (or two) always shows up.
Has anyone had to deal with Google hoarding pages? Is there a more efficient way of dealing with this?