lists

When visiting https://lists.zom.bi/lists/1/edit schleuder-web throws an error. I can't see if that's a problem in our configuration or upstream.
excerpt from the relevant log at /schleuder-web/log/production.log inside of the schleuder-web container

F, [2020-06-11T12:20:38.569496 #8] FATAL -- : [11bce044-75b0-4105-a890-f004d6599a4e]   
F, [2020-06-11T12:20:38.569560 #8] FATAL -- : [11bce044-75b0-4105-a890-f004d6599a4e] ActionView::Template::Error (undefined method `deliver_selfsent' for #<List:0x0000564800d95e38>):
F, [2020-06-11T12:20:38.569678 #8] FATAL -- : [11bce044-75b0-4105-a890-f004d6599a4e]     22:     %fieldset
[11bce044-75b0-4105-a890-f004d6599a4e]     23:       %legend Send control
[11bce044-75b0-4105-a890-f004d6599a4e]     24:       = checkbox f, :send_encrypted_only, "Only send messages if they can be encrypted to the subscribed receiver (does not apply to resend messages)."
[11bce044-75b0-4105-a890-f004d6599a4e]     25:       = checkbox f, :deliver_selfsent, "Should e-mails be delivered to the original subscribed sender? (Works only with signed emails.)"
[11bce044-75b0-4105-a890-f004d6599a4e]     26: 
[11bce044-75b0-4105-a890-f004d6599a4e]     27:     %fieldset
[11bce044-75b0-4105-a890-f004d6599a4e]     28:       %legend Receive control
F, [2020-06-11T12:20:38.569703 #8] FATAL -- : [11bce044-75b0-4105-a890-f004d6599a4e]   
F, [2020-06-11T12:20:38.569740 #8] FATAL -- : [11bce044-75b0-4105-a890-f004d6599a4e] app/helpers/application_helper.rb:37:in `checkbox'
[11bce044-75b0-4105-a890-f004d6599a4e] app/views/lists/_form.html.haml:25:in `block in _app_views_lists__form_html_haml___3892246886173049391_47433626430480'
[11bce044-75b0-4105-a890-f004d6599a4e] app/views/lists/_form.html.haml:4:in `_app_views_lists__form_html_haml___3892246886173049391_47433626430480'
[11bce044-75b0-4105-a890-f004d6599a4e] app/views/lists/edit.html.haml:3:in `_app_views_lists_edit_html_haml___2210632198003985092_47433601730860'