The domain did expire, though I was never made aware of the upcoming expiration. My assumption is that there was some glitch between Namecheap, Google, and the .co domain authority... but I still don’t know exactly how my domain expired so silently. All my other domains were purchased through Google, this one was transferred in.
It really was a massive headache. I have no idea how long it would have taken me to notice (site is my authoritative presence on the web, but is a static personal page — no marketing or sales) and my email is a light trickle of messages by design: bills, bank statements, close personal relationships. Fortunately my brother told me his wedding invite bounced a day after going offline so I could follow up relatively quickly.
I filed a ticket with Google and got first line support within an hour. They confirmed it was still in Googles system. Then I was assigned a Senior Specialist who called me on Monday to confirm ownership. It is now Wednesday and my DNS records are still inaccessible.
If I were you I would definitely set an independent annual reminder to check your domain status, just in case.