Hrm. Good point. At some point I remember some SEO guru or other claiming that long-duration domain name registrations were good for SEO, but looking at it now, it seems as though that was a correlation !== causation, as MS, Goog, et al register their domain names for decades at a time, and also tend to have high search rankings.

As for the rest, chalk it up to my over-active imagination, compounded with that bad knowledge. SSL is an SEO boost (according to a random Googling), and if domain name expiration was a factor, it made sense to me that SSL expiry would factor too.

TLDR, I was a dumb.