gunicorn via mod_proxy is redirecting outside of the project's scope, despite ProxyPassReverse

I have a WSGI-app (a Django project) running under gunicorn on 127.0.0.1:18731 and I use Apache with mod_proxy to redirect requests from http://example.com/my-project/* to http://127.0.0.1:18731/*. Static files are stored outside of /my-project/. If the Django app does not need to redirect anything, this works just fine, but if it tries to redirect a request (e.g. to add a trailing slash to http://example.com/my-project/foo), it ends up removing /my-project/ from the URL, leaving me with the invalid URL http://example.com/foo/.

My mod_proxy configuration is as follows:

<Proxy *>
    Order deny,allow
    Allow from all
</Proxy>
ProxyRequests On
ProxyPass /my-project/ http://127.0.0.1:18731/ retry=0
ProxyPassReverse /my-project/ http://127.0.0.1:18731/ retry=0
ProxyPreserveHost On
ProxyErrorOverride Off

I do not want to force Django to prefix /my-project/ to all of its URLs, in the interest of portability. Apache should apparently be handling the prefix on its own with the ProxyPassReverse line. What am I doing wrong?