Prom query Issue - Data mismatch in different time frames

[sreehari M V]

Hi Team,

We use a discrete plugin(panel) in Grafana to display the data from blackbox_exporter to track the end-point(URL) availability and Prometheus data retention period is 50 days. This panel shows URL available and  unavailable time in percentage.

Issue is smaller down time (E.g: 502 return code for 1hr )  is getting  ignored when we select a larger time range in Grafana (above 1 month) and the panel is showing 100% URL available.  But if we select a smaller time frame in Grafana, the URL unavailable time is displayed.

Suspecting issue with  below query mentioned in panel. Can somebody please provide a solution for this issue ?

Prom query Used in Grafana discrete plugin

probe_httpd_status_code{instance="https://xxxxxxx",job=blackbox-generic-endpoints"}

Prometheus Version - 2.31.0

Blackbox exporter - 0.13.0

Grafana Version - 6.7.4

Scrape_interval: 30s

Thanks and regards

SreeHari