Nginx reverse proxy corrupting filenames

I have a Subversion vesion 1.14.1 running behind a reverse proxy
implemented by nginx version 1.18.0 on a Ubuntu 22.04 server.

I'm having problems renaming files in it. I came up with the following
procedure to reproduce the problem:

> $ export LANG=C.UTF-8
> $ export LANGUAGE=en
> $ REPO=https://svn.domain.mine/repo
>
> $ svn co $REPO/trunk repo
> Checked out revision 19.
>
> $ cd repo
>
> $ echo doit >'plano de acao.txt'
>
> $ svn add 'plano de acao.txt'
> A         plano de acao.txt
>
> $ svn commit -m'add file'
> Adding         plano de acao.txt
> Transmitting file data .done
> Committing transaction...
> Committed revision 20.
>
> $ ls -lA
> total 8
> drwxrwxr-x 4 gustavo gustavo 4096 Jun 20 13:39  .svn
> -rw-rw-r-- 1 gustavo gustavo    5 Jun 20 13:40 'plano de acao.txt'
>
> $ svn mv 'plano de acao.txt' 'action plan.txt'
> A         action plan.txt
> D         plano de acao.txt
>
> $ svn commit -m'rename file'
> Adding         action plan.txt
> Deleting       plano de acao.txt
> Committing transaction...
> Committed revision 21.
>
> $ ls -lA
> total 8
> drwxrwxr-x 4 gustavo gustavo 4096 Jun 20 13:39  .svn
> -rw-rw-r-- 1 gustavo gustavo    5 Jun 20 13:40 'action plan.txt'
>
> $ svn up
> Updating '.':
> svn: E175009: The XML response contains invalid XML
> svn: E130003: Malformed XML: no element found at line 10
>
> $ cd ..
>
> $ rm -rf repo
>
> $ svn co $REPO/trunk repo
> A    repo/action%20plan.txt
> Checked out revision 21.
>
> $ cd repo
>
> $ ls -lA
> total 8
> drwxrwxr-x 4 gustavo gustavo 4096 Jun 20 13:42 .svn
> -rw-rw-r-- 1 gustavo gustavo    5 Jun 20 13:42 action%20plan.txt
>
> $ svn up
> Updating '.':
> At revision 21.

Note the error message in the first "svn up" and also that the space
in the filename is checked out as "%20".

I can reproduce this problem only when I access the repository via an
URL that goes through the nginx reverse proxy. If I try via an URL
that goes directly to Apache httpd or locally (file://) the problem
does not happen.

This is the Nginx's server configuration I'm using for the proxy:

> server {
>   listen      443 ssl;
>   server_name svn.domain.mine;
>
>   client_body_timeout 3600s;
>   client_max_body_size 10m;
>   keepalive_timeout 3600s;
>   send_timeout 3600s;
>
>   location / {
>     proxy_pass       http://localhost:3691;
>     proxy_set_header X-Forwarded-For $remote_addr;
>     proxy_set_header Host            $host;
>     proxy_buffering off;
>     proxy_request_buffering off;
>
>     # See https://sigterm.sh/2012/10/09/nginx-apache-2-and-subversion-502-bad-gateway-error/
>     set $fixed_destination $http_destination;
>     if ( $http_destination ~* ^https(.*)$ )
>     {
>       set $fixed_destination http$1;
>     }
>     proxy_set_header Destination $fixed_destination;
>   }
> }

I wasn't able to find any mention of a similar problem via Google or
in Subversion's Jira.

Can you help me figure this out, please?

--
Gustavo