UserFeedback Form sends data to http:// Link on a https:// page

I have a sentry installation behind a SSL Reverse Proxy.

Everything is https:

Sentry/Django settings
$ sentry django diffsettings

Nginx Settings
# nginx conf reverse proxy
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto $scheme;

But sending the feedback formular gives an error, cause the form action is http.

Comes from the endpoint
var endpoint = /**/"";/**/'';

in the ajax response for:

the template part:
'endpoint': mark_safe('*/' + json.dumps(request.build_absolute_uri()) + ';/*'),
So it should django related

Bug or misconfiguration? Have I overseen a param?

I posted my solution here.