Setting the interval makes queries not fetch data

[fdw]

I'm trying to create a graph panel with the current (not 7.0) grafonnet lib. The panel should have a "min step" of 120, and according to #76, this is called interval in grafonnet. However, when I set interval, I can still create the panel, but it doesn't fetch data at all.

If I then remove the "min step" in the GUI, the query is executed as expected. I can then add the same value again for "min step", and it still works.

Am I doing something wrong? Is there a workaround that does not involve manual work?