Bar gauge panel fails when null value - possible bug


I am using Grafana with the Zabbix plugin to display the current network status of multiple hosts in a bar gauge panel. I have it configured to query a host group for the current ping status and transform null to zero.

When one of the hosts returns a null value or no data, the entire panel disappears, and the red broken-heart alert appears in the corner. When I duplicate the panel, it appears normally the second time with the correct information, but returns to the error state when the page is refreshed.

Is this a bug? How can I work around it?