Hmm, it’s a combination of specifically GitHub’s TLS1.3 stack which seems unique and Windows schannel behavior that cause the socket to act differently than expected. It’s fixed by curl 7.87 CURLE_RECV_ERROR schannel: SEC_E_DECRYPT_FAILURE · Issue #9431 · curl/curl · GitHub
So I’ll end up updating the nightlies to it but the 6.0 branch is kind of stuck