Aha, correct. Loaded up the website that appeared downgraded, it's still HTTP/2 in the incognito window, and chrome://net-internals/#http2 does confirm that it

Aha, correct. Loaded up the website that appeared downgraded, it's still HTTP/2 in the incognito window, and chrome://net-internals/#http2 does confirm that it is in-fact real HTTP/2 (not the extension being odd). Why would this behaviour happen? I don't understand why it does the initial session in HTTP/2 but then drops to SPDY upon further requests