Can't delete circle "In CircleDestroy.php line 105: Circle is managed from an other app"

I have made several attempts from the web interface to delete a circle, which always failed with the error message "cannot delete contact". This error message persisted even after I manually removed all members from the circle

Next I tried to delete the circle through OCC

That's where I got the above error message.

Apparently, the error is generated by this function:

      public function verify(FederatedEvent $event): void {
                $circle = $event->getCircle();
                if ($circle->isConfig(Circle::CFG_APP)) {
                        throw new FederatedItemBadRequestException(
                                StatusCode::$CIRCLE_DESTROY[120],
                                120
                        );
                }

                $initiator = $circle->getInitiator();

                $initiatorHelper = new MemberHelper($initiator);
                $initiatorHelper->mustBeOwner();

                $event->setOutcome($this->serialize($circle));
        }

This is what I see in nextcloud.log:

{"reqId":"1YY35kFLsWcn7CHRIUyr","level":3,"time":"2024-05-08T07:28:51+00:00","remoteAddr":"172.70.231.17","user":"jr","app":"circles","method":"DELETE","url":"/ocs/v2.php/apps/circles/circles/lXekW33g9T66L76k9eF1QDRA4SvqBow","message":"{\"circleId\":\"lXekW33g9T66L76k9eF1QDRA4SvqBow\"}","userAgent":"Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:125.0) Gecko/20100101 Firefox/125.0","version":"28.0.5.1","exception":{"Exception":"OCA\\Circles\\Exceptions\\FederatedItemBadRequestException","Message":"Circle is managed from an other app","Code":120,"Trace":[{"file":"/var/www/cloud.****/apps/circles/lib/Service/FederatedEventService.php","line":178,"function":"verify","class":"OCA\\Circles\\FederatedItems\\CircleDestroy","type":"->"},{"file":"/var/www/cloud.***/apps/circles/lib/Service/CircleService.php","line":265,"function":"newEvent","class":"OCA\\Circles\\Service\\FederatedEventService","type":"->"},{"file":"/var/www/cloud.***/apps/circles/lib/Controller/LocalController.php","line":172,"function":"destroy","class":"OCA\\Circles\\Service\\CircleService","type":"->"},{"file":"/var/www/cloud.*/lib/private/AppFramework/Http/Dispatcher.php","line":230,"function":"destroy","class":"OCA\\Circles\\Controller\\LocalController","type":"->"},{"file":"/var/www/cloud.****/lib/private/AppFramework/Http/Dispatcher.php","line":137,"function":"executeController","class":"OC\\AppFramework\\Http\\Dispatcher","type":"->"},{"file":"/var/www/cloud.*/lib/private/AppFramework/App.php","line":184,"function":"dispatch","class":"OC\\AppFramework\\Http\\Dispatcher","type":"->"},{"file":"/var/www/cloud*/lib/private/Route/Router.php","line":315,"function":"main","class":"OC\\AppFramework\\App","type":"::"},{"file":"/var/www/cloud.*/ocs/v1.php","line":65,"function":"match","class":"OC\\Route\\Router","type":"->"},{"file":"/var/www/cloud.*/ocs/v2.php","line":23,"args":["/var/www/cloud.*/ocs/v1.php"],"function":"require_once"}],"File":"/var/www/cloud.*/apps/circles/lib/FederatedItems/CircleDestroy.php","Line":105,"message":"{\"circleId\":\"lXekW33g9T66L76k9eF1QDRA4SvqBow\"}","exception":{"class":"OCA\\Circles\\Exceptions\\FederatedItemBadRequestException","status":400,"code":120,"message":"Circle is managed from an other app"},"CustomMessage":"{\"circleId\":\"lXekW33g9T66L76k9eF1QDRA4SvqBow\"}"}}

This is what I see when I try to delete the circle using occ:

$ occ circles:manage:destroy ***

In CircleDestroy.php line 105:

  Circle is managed from an other app

Start with apps/circles/lib/FederatedItems/CircleDestroy.php at line 105, then trace the deletion flow through FederatedEventService.php, CircleService.php, and LocalController.php as shown in the log. Reproduce the failure through the web interface and occ circles:manage:destroy, and determine what should allow deletion when the circle is no longer managed by another app.