I thought it was weird that some things I knew to be available were suddenly showing "remind me" instead of "play now" on Netflix.

It seems that Netflix thinks I might be spoofing my location since I'm using a Hurricane Electric IPv6 tunnel. Fairly, nothing in the tunnelbroker.net UI stops me from choosing a tunnel exit elsewhere on the planet. They don't offer one in my city, so I've chosen Denver for one and Chicago for the other. This wasn't any kind of purposeful decision on my part; I'm geographically between them, and couldn't remember which I'd chosen for the one (which was years ago, repurpose with this new network on my WAN router) when I created the second one (use for the WiFi router).

After some poking around, I found a very simple set of "make Netflix IPv6 disappear" solutions at https://github.com/cdhowie/netflix-no-ipv6-dns-proxy. The easiest is to leverage the router's built-in dnsmasq caching name server and configure it to "return null" for Netflix requests. In a simple configuration file, a number of Netflix domains are listed and each will return an empty (technically :: -- all zeroes) response to IPv6 queries for the Netflix domains. A couple other changes to configure the router to offer its address for DNS to the DHCP clients, and to intercept all DNS requests, and the fix is in.

Now Netflix works, and the shows have returned to "play now" instead of "remind me."

I've already asked if my new ISP has any plans to move forward with supporting IPv6, even if "just" 6rd with my static IP addresses. They've decided not to pursue IPv6 for now (which seems weird, because all their gear supports it, I'm sure), and suggested the tunnels work well enough. Clearly, they do, but also they have some limitations.