Also, I came across what seems to be a mild font rendering glitch with Calibri. Downloading metadata with bold text shows what seems to be a different font:
The HTML shows a font-weight of 600:
Code:
<p align="justify" style="font-weight: 600">Asimov Science Fiction Readers' Choice, and RT Reviewers' Choice.</p>
But selecting the text in the MDE and clicking 'bold' again changes the font-weight to 700 and fixes it:
All my previous books have font-weight of 600 for bold.
ANOTHER EDIT: I'll make a ticket.