Bump. Note that I have the same problem (the same in terms of your title and log errors), but I do not use Steam, but Epic Online Services instead (via EOSCore plugin).
In my case the error comes to light when I (successfully) connect to server, than disconnect and connect right after I exited. It seems like client or server thinks some connection data is still valid (not cleared), so after reconnect client refuses to make a handshake and after some time it is disconnected by timeout, as if the client did not ever being connected.
Still searching the solution.