When #16043 was merged, a new method multiple_with_filter? has been introduced in hosts_controller and exposed via helper_method. It's also being used in generic helper HostsAndHostgroupsHelper#multiple_filter and it works since most actions are implemented in hosts controller. If plugin adds actions (e.g. foreman_openscap - assign compliance policy), a plugin controller is used and the method is undefined. This method should be probably available globally or the helper should duplicate the logic and check for search param presence. I believe this affects all plugins introducing custom bulk actions and should be fixed in 1.15 branch.