I can only explain the content of the note. I can't explain the rendering by Primal, which is confused. I'm sure it's an edge case where an assumption that was made wasn't correct.
Discussion
Think you're right. Ditto didn't render it at all. Maybe the naddr paste-in was typo-ed, and in such cases Ditto doesn't render it at all, but Primal has some logic to still render typo-ed pastes, and in this case it went a little kooky on the render.