servers returns "Invalid Host header" inside alpine when connecting via ssl

Question

First of all, this question is not about how to fix this, but rather about why it happens.

Exact same curl (exact same version curl/7.65.1) with exact same request produces different results.

• Why the certificate chain is different?
• How server response depends on ssl connection flow? (Alpine get response body "Invalid host header", host OS downloads file w/o any issues)?
• Why http version is different? How do the server and client agree on protocol version? Running the same command with --http curl flag fixes the issue.

docker run -i -t alpine /bin/sh:

apk add curl
curl -kfSL https://nginx.org/download/nginx-1.15.3.tar.gz -o nginx.tar.gz -vvv

Output:

*   Trying 95.211.80.227:443...
* TCP_NODELAY set
* Connected to nginx.org (95.211.80.227) port 443 (#0)
* ALPN, offering h2
* ALPN, offering http/1.1
* successfully set certificate verify locations:
*   CAfile: /etc/ssl/certs/ca-certificates.crt
  CApath: none
* TLSv1.3 (OUT), TLS handshake, Client hello (1):
* TLSv1.3 (IN), TLS handshake, Server hello (2):
* TLSv1.2 (IN), TLS handshake, Certificate (11):
* TLSv1.2 (IN), TLS handshake, Server key exchange (12):
* TLSv1.2 (IN), TLS handshake, Server finished (14):
* TLSv1.2 (OUT), TLS handshake, Client key exchange (16):
* TLSv1.2 (OUT), TLS change cipher, Change cipher spec (1):
* TLSv1.2 (OUT), TLS handshake, Finished (20):
* TLSv1.2 (IN), TLS handshake, Finished (20):
* SSL connection using TLSv1.2 / ECDHE-RSA-AES128-GCM-SHA256
* ALPN, server accepted to use h2
* Server certificate:
*  subject: CN=localhost
*  start date: Jul  8 19:13:11 2019 GMT
*  expire date: Aug  7 19:13:11 2019 GMT
*  issuer: CN=localhost
*  SSL certificate verify result: self signed certificate (18), continuing anyway.
* Using HTTP2, server supports multi-use
* Connection state changed (HTTP/2 confirmed)
* Copying HTTP/2 data in stream buffer to connection buffer after upgrade: len=0
* Using Stream ID: 1 (easy handle 0x55e3e4a37540)
> GET /download/nginx-1.15.3.tar.gz HTTP/2
> Host: nginx.org
> User-Agent: curl/7.65.1
> Accept: */*
> 
* Connection state changed (MAX_CONCURRENT_STREAMS == 4294967295)!
< HTTP/2 200 
< x-powered-by: Express
< content-type: text/html; charset=utf-8
< content-length: 19
< etag: W/"13-OxsTL6IB85fkJxv9HO8uum0slCI"
< 
* Connection #0 to host nginx.org left intact
Invalid Host header

Same curl command works completely fine from my host machine (Archlinux bleeding edge) even without insecure (-k)option.

  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0*   Trying 95.211.80.227:443...
* TCP_NODELAY set
* Connected to nginx.org (95.211.80.227) port 443 (#0)
* ALPN, offering h2
* ALPN, offering http/1.1
* successfully set certificate verify locations:
*   CAfile: /etc/ssl/certs/ca-certificates.crt
  CApath: none
} [5 bytes data]
* TLSv1.3 (OUT), TLS handshake, Client hello (1):
} [512 bytes data]
* TLSv1.3 (IN), TLS handshake, Server hello (2):
{ [108 bytes data]
* TLSv1.2 (IN), TLS handshake, Certificate (11):
{ [2621 bytes data]
* TLSv1.2 (IN), TLS handshake, Server key exchange (12):
{ [333 bytes data]
* TLSv1.2 (IN), TLS handshake, Server finished (14):
{ [4 bytes data]
* TLSv1.2 (OUT), TLS handshake, Client key exchange (16):
} [70 bytes data]
* TLSv1.2 (OUT), TLS change cipher, Change cipher spec (1):
} [1 bytes data]
* TLSv1.2 (OUT), TLS handshake, Finished (20):
} [16 bytes data]
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0* TLSv1.2 (IN), TLS handshake, Finished (20):
{ [16 bytes data]
* SSL connection using TLSv1.2 / ECDHE-RSA-AES256-GCM-SHA384
* ALPN, server accepted to use http/1.1
* Server certificate:
*  subject: CN=nginx.org
*  start date: May 14 19:45:30 2019 GMT
*  expire date: Aug 12 19:45:30 2019 GMT
*  subjectAltName: host "nginx.org" matched cert's "nginx.org"
*  issuer: C=US; O=Let's Encrypt; CN=Let's Encrypt Authority X3
*  SSL certificate verify ok.
} [5 bytes data]
> GET /download/nginx-1.15.3.tar.gz HTTP/1.1
> Host: nginx.org
> User-Agent: curl/7.65.1
> Accept: */*
> 
{ [5 bytes data]
* Mark bundle as not supporting multiuse
< HTTP/1.1 200 OK
< Server: nginx/1.15.7
< Date: Wed, 10 Jul 2019 13:03:16 GMT
< Content-Type: application/octet-stream
< Content-Length: 1022881
< Last-Modified: Tue, 28 Aug 2018 15:40:55 GMT
< Connection: keep-alive
< Keep-Alive: timeout=15
< ETag: "5b856d07-f9ba1"
< Accept-Ranges: bytes

P.S. I'm aware of this response