nginx proxy 502 error after update to crossbar==19.10.1

Hello,
after crossbar update to 19.10.1, nginx throws 502, crossbar is started without any errors, but proxy doesn't works for some reason...

after that I reverted to crossbar 19.6.2, restarted crossbar server and reloaded app in browser and everything is fine - connected.

working setup:

 Crossbar.io        : 19.6.2
   txaio            : 18.8.1
   Autobahn         : 19.10.1
     UTF8 Validator : autobahn
     XOR Masker     : autobahn
     JSON Codec     : stdlib
     MsgPack Codec  : msgpack-0.6.2
     CBOR Codec     : cbor-1.0.0
     UBJSON Codec   : ubjson-0.14.0
     FlatBuffers    : flatbuffers-1.11
   Twisted          : 19.7.0-EPollReactor
   LMDB             : 0.97/lmdb-0.9.22
   Python           : 3.5.3/CPython
 Frozen executable  : no
 Operating system   : Linux-4.9.0-9-amd64-x86_64-with-debian-9.9
 Host machine       : x86_64
 Release key        : RWTS7Lf+Zks97Pu2hRHkjaVPjjbDCUVc2tOAHjsd1a1W5cKKciAoSIRE

non-working setup (after update)

 Crossbar.io        : 19.10.1
   txaio            : 18.8.1
   Autobahn         : 19.10.1
     UTF8 Validator : autobahn
     XOR Masker     : autobahn
     JSON Codec     : stdlib
     MsgPack Codec  : msgpack-0.6.2
     CBOR Codec     : cbor-1.0.0
     UBJSON Codec   : ubjson-0.14.0
     FlatBuffers    : flatbuffers-1.11
   Twisted          : 19.7.0-EPollReactor
   LMDB             : 0.97/lmdb-0.9.22
   Python           : 3.5.3/CPython
 Frozen executable  : no
 Operating system   : Linux-4.9.0-9-amd64-x86_64-with-debian-9.9
 Host machine       : x86_64
 Release key        : RWRlUB1klnmQWao9JKtkTu5GeI74LHoQnhH8q7vvT+oRlbyWRmd74kbw

NGINX upstream config

        map $http_upgrade $connection_upgrade {
            default upgrade;
            '' close;
        }

        upstream websocket {
            server 127.0.0.1:3110;
        }

NGINX proxy server config

server {
    listen 80;
    server_name ws.xxxxxx.com;

    access_log off;
    log_not_found off;

    location / {
        expires -1;
    }

    location /ws {
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
        proxy_set_header Host $host;

        proxy_pass http://websocket;
        proxy_redirect off;

        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "upgrade";
    }

        location ~ /\. {
            log_not_found off;
            deny all;
        }
}

crossbar transports layer (working setup on crossbar==19.6.2)

.
.
.
      "transports": [
        {
          "type": "websocket",
          "endpoint": {
            "type": "tcp",
            "port": 3110
          },
          "options": {
            "enable_webstatus": false,
            "max_frame_size": 1048576,
            "max_message_size": 1048576,
            "auto_fragment_size": 65536,
            "fail_by_drop": true,
            "open_handshake_timeout": 6000,
            "close_handshake_timeout": 5000,
            "auto_ping_interval": 6000,
            "auto_ping_timeout": 6000,
            "auto_ping_size": 4,
            "compression": {
              "deflate": {
                "request_no_context_takeover": false,
                "request_max_window_bits": 11,
                "no_context_takeover": false,
                "max_window_bits": 11,
                "memory_level": 4
              }
            }
          }
        }
      ]

.
.
.

Reproduce the reported 502 with the supplied NGINX upstream and /ws proxy configuration, comparing Crossbar.io 19.6.2 and 19.10.1 on the stated Python and Linux setup. Start with the Crossbar WebSocket transport configuration and the version change; done means the 19.10.1 setup connects successfully through NGINX without the 502 regression.