522 Origin Connection Time-out
Three times for the stats endpoint, probably successive queries. I don't have full headers, but this one looks to be from CloudFlare:
Cloudflare could not negotiate a TCP handshake with the origin server.
Basically, nothing a user can do; report to support if it is persistent as it's either a CloudFlare or chess.com configuration problem or broken hardware or ...
More details:
https://support.cloudflare.com/hc/en-us/articles/200171906-Error-522-Connection-timed-out
Sorry, @bcurtis: I reported what I had. There are probably debugging options I could use to get the full headers, but by default my scripts only print the status line. For a non-reproducible problem I was a bit stuck.
As noted in my post #18 I wasn't even sure if the errors were from sequential requests and responses, as the code wasn't running in verbose or debug mode so successes were silent.