Once a set of invitations has been sent out in bulk, the message that’s sent as a result contains the log:
As you can see in the screenshot, it’s fenced in a code block, and apostrophes are being interpreted as the start/end of strings, so you get runs of red and runs of black.
Additionally, the log itself contains HTML to bold the email addresses and provide a link to the user summary page, but this is unparsed and thus not particularly useful, instead just adding noise.
I would suggest that the log be output as is or as a list, and the HTML either stripped or interpreted.