Nevermind about that "another day" bit đ. Got a login redirect pretty quickly.
@z64
Refreshing the page does not work. Presumably it's just because of the URL: https://kagi.com/signin. This shows me a signin form regardless of whether I'm signed in. But, navigating directly to kagi.com as you say indicates I'm signed in. In fact, I can simply repeat the address bar search from the signin page I've been redirected to and it works just fine.
So you're definitely right, that my login is not actually invalidated. I'm just somehow being redirected to /signin.
After the redirect, I open the console to see nothing but some CSP warnings:
Content Security Policy: Couldnât process unknown directive âreport-toâ
Content Security Policy: Ignoring â'unsafe-inline'â within script-src: âstrict-dynamicâ specified
Content Security Policy: Ignoring âhttps://*.kagi.comâ within script-src: âstrict-dynamicâ specified
Still need to take some time to try to dig in to uMatrix settings to figure out what's going on...