Avoid coarse sampling in custom dashboard dygraph charts

After upgrading from Netdata v1.37 to v1.44 I noticed that the Dygraphs charts on a custom dashboard were showing values older than 30 minutes with a straight line on data sampled at successive 30’ intervals. Scrolling the timeline restores full resolution, while clicking on “Chart Reset” goes back to the 30’ sampling. How can I have the timelines always plotted without coarse sampling?

Here is the chart’s definition and its appearance with and without interpolation.

   <div data-netdata="H.temperature"
      data-colors="#000080 #ff0000"

I searched for a parameter to tweak by looking in the Netdata documentation, the Dygraphs documentation and also for dataattribute in the dashboard source code, but didn’t find a setting that seemed relevant.