I’ve had that same problem before, and never really reached a solution. I think you’re right – it is likely that it can’t parse the information it needs properly from the page you liked.
One way to dig in to it could be to see if that same URL, when pasted in to the ‘URL’ section when creating a post manually in WordPress (not via Micropub), gets the correct values picked up. That could point whether it is specifically a parsing issue or a Micropub issue.