Well, first off is the part where Thunderbird threw it into my Junk folder. Apparently there was sufficient pattern in the outgoing email to cause Thunderbird (via Spam Assassin, I think) to label it as such. I’ve never had any issues with email from SP, before - they have always (until this) landed in my Inbox.
The next trigger was the link to “sitepointforums.com”. Maybe that was a commonly used FQDN before I created my account, here, IDK. But for as long as I’ve had my SPF account (created shortly before the conversion to Discourse), I think the URL was either “forums.sitepoint.com” or (as now) “community.sitepoint.com”. So seeing that different FQDN made me think of hackers/phishers creating a bogus-but-legit-sounding domain in order to get information.
Off the top of my head, that’s all that I can think of. I don’t have access to the email, right now, so can’t bring it up to comment upon it, further.