visual studio code remote ssh over ssh proxy

I am trying to use vs-code's remote-ssh extension to connect to a server over a ssh tunnel. The server is part of an internal cluster that does not have a public ip address, and I connect to it via a proxy in the cluster using the method outlined in link:

# ~/.ssh/config
Host internal*
User root
ProxyCommand ssh user@firewall 'nc %h %p'

When I try to connect to the internal server, I get the following error dialog:

Could not establish connection to "internal-server". The process tried to write to a nonexistent pipe.

The output window's log:

remote-ssh@0.45.6
win32 x64
SSH Resolver called for "ssh-remote+internal-server", attempt 1
SSH Resolver called for host: internal-server
Setting up SSH remote "internal-server"
Using commit id "........" and quality "stable" for server
Testing ssh with ssh -V
ssh exited with code: 0
Got stderr from ssh: OpenSSH_for_Windows_7.7p1, LibreSSL 2.6.5
Running script with connection command: ssh -o ClearAllForwardings=true internal-server bash
Install and start server if needed
> 
Got some output, clearing connection timeout
> ]0;C:\WINDOWS\SYSTEM32\cmd.exe
> 
> CreateProcessW failed error:2
> 
> posix_spawn: No such file or directory
> The process tried to write to a nonexistent pipe.
> 
"install" terminal command done
Install terminal quit with output: The process tried to write to a nonexistent pipe.
Received install output: The process tried to write to a nonexistent pipe.
The process tried to write to a nonexistent pipe
TELEMETRY: {"eventName":"resolver","properties":{"outcome":"failure","reason":"OfflineError"},"measures":{"resolveAttempts":1,"retries":1}}
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How can I use vs-code's remote-ssh to connect to computers behind a proxy/firewall?