Explore and Alert rules query results are different

I’m using Grafana 9.1.6 and InfluxDB 1.8. I have the following data being fed into influxdb:

app_status,host=server_a status="starting"
app_status,host=server_b status="healthy"
app_status,host=server_c status="unhealthy"

I’m trying to create an alert rule to notify me when an application status turns to unhealthy.
However the same query returns different results in the “Explore” page and in the “Create alert rule” page.
I’m running the following query:

SELECT last(*) FROM "app_status" WHERE $timeFilter GROUP BY host LIMIT 1

Explore returns:

time host last_status
server_a starting
server_b healthy
server_c unhealthy

The same exact query in “Create alert rule” page returns: No Data.

Is this a bug? Or am I missing something?

Hi! Alerting needs numerical data, it cannot alert on textual data like in the example.