Apologies, it looks like I'd miscounted on the ghost.org link, which does in fact exist and render properly. It was the plus.google.com URLs which aren't

Apologies, it looks like I'd miscounted on the ghost.org link, which does in fact exist and render properly. It was the plus.google.com URLs which aren't being cut down properly and displaying the G+ icon the way they should and instead appear as a generic share icon.

The other is for syndicating via email (which I imagine isn't done often?) and appears on line 205 of
https://github.com/dshanske/syndication-links/blob/52160d913fcf6d41406f468ee13323bc90a983b5/includes/class-syn-meta.php as `'mailto:' => 'mail',`
Unless I'm formatting it painfully wrong, mailto:XXX links show up with the generic share icon instead of a mail icon.