Why does "relative time" / "time shift" default to 1h?

any idea why this happens?

It’s causing Grafana to stop querying InfluxDB. When I set “time shift” explicitely to “0h” it queries again on pressing reload. When it’s at the default 1h it does not. I’ve verified this by looking at the InfluxDB log.

Grafana 7.0.5 and InfluxDB 1.8.0