'Bad file descriptor' when using forwarded gpg-agent socket on Linux

Question

I'm using gpg4win on my Windows client to sign commits to Git with my Yubikey. This is working fine and I'm trying to accomplish the same on a remote Linux machine by forwarding my S.gpg-agent.extra socket on Windows to my remote Linux machine, using SSH. I used this guide to accomplish this.

The socket forwarding seems to work as I can see the socket on my remote Linux machine. However, executing something like gpg --list-secret-keys on my remote Linux machine returns:

connect to /c/Users/martijn/AppData/Local/gnupg/S.gpg-agent.extra port -2 failed: Bad file descriptor

I've added the following host configuration to my .ssh/config file in my Windows home:

Host my-remote-host.net
    HostName        my-remote-host.net
    User            martijn
    IdentityFile    ~/.ssh/id_rsa
    RemoteForward   /run/user/8898/gnupg/S.gpg-agent /c/Users/martijn/AppData/Local/gnupg/S.gpg-agent.extra
    ExitOnForwardFailure yes

Besides the GPG issue, the SSH tunnel itself is fully functional. I also verified that the S.gpg-agent.extra file exists in the given directory. Please feel free to ask for more information, if necessary.

What am I doing wrong?