I just replaced a tumblr website for a client with a brand new Wordpress site. And when running it through the Facebook debugger, I get this error:
The object at 'http://example.com/' previously had type 'tumblr-feed:tumblelog' and cannot be changed to an object of type 'website' to avoid data corruption of existing actions.
I Googled "Cannot change og_type" (in quotes) and got literally zero results (well now it seems there are results stemming from this question). Am I really doomed to Facebook data mismatch?
Per the error message
... cannot be changed to an object of type 'website' to avoid data corruption of existing actions.
If the og:type were changed for a URL, any existing user posts linking to it or sharing it, any Open Graph actions referencing it, as well as any likes of the URL would become broken and the user's profiles would be missing content they'd posted before.
I don't believe there's any way around this, as it's an intentional restriction to avoid breaking existing posts, likes, actions, etc referencing a URL. If the posts were broken, content would be removed from or mangled on the user's timeline.
A possible workaround if you want to have a 'new' object at that URL is to use my instructions in this answer about moving URLs to put a Like button on the URL you're trying to change (let's call it A), but pointing to a slightly different, new URL (let's call it B) , and then use the redirect mechanism in my answer to bounce users landing at URL B back to A, but serve the metdata describing 'A' on URL B if the Facebook crawler accesses it