In the project administration, on the "Members" tab, for unknown reasons one of the users that is project members can be linked to a user group that cannot be found. It leads to an "Internal Server Error" of the page and an exception in the logs like:

This ugroup id is invalid: 282:
#0 /usr/share/tuleap/src/common/Project/Admin/ProjectMembers/ProjectMembersController.php(399): Tuleap\Project\Admin\ProjectMembers\ProjectMembersController->getMinimalUGroupPresenter()
#1 /usr/share/tuleap/src/common/Project/Admin/ProjectMembers/ProjectMembersController.php(362): Tuleap\Project\Admin\ProjectMembers\ProjectMembersController->getUGroupsPresenters()
#2 /usr/share/tuleap/src/common/Project/Admin/ProjectMembers/ProjectMembersController.php(266): Tuleap\Project\Admin\ProjectMembers\ProjectMembersController->getFormattedProjectMembers()
#3 /usr/share/tuleap/src/common/Project/Admin/ProjectMembers/ProjectMembersController.php(251): Tuleap\Project\Admin\ProjectMembers\ProjectMembersController->display()
#4 /usr/share/tuleap/src/common/Request/FrontRouter.php(250): Tuleap\Project\Admin\ProjectMembers\ProjectMembersController->process()
#5 /usr/share/tuleap/src/common/Request/FrontRouter.php(97): Tuleap\Request\FrontRouter->routeHandler()
#6 /usr/share/tuleap/src/www/index.php(50): Tuleap\Request\FrontRouter->route()
#7 {main}

The page should not crash.