From what was said, MerlinMama has the option set in the editor to add update the metadata when opening the book. I know that I had that option set. The comments are because there has been a change and these images weren't in the books before the latest calibre release.
For my report, I meant to be commenting on the "-1.cover" as the id. From the comment with the code check-in, I was expecting the id or a property to be set that an application would use to find the image. Or that it would be in a standard location.
What I hadn't noticed was the earlier line in the OPF:
Code:
<meta name="cover" content="-1.cover"/>
And that's obviously the way to find the cover image. That just leaves it as a weird looking id

And that makes me wonder how many applications would reject it as invalid.
Edit: Thanks for the option.