[Observium] CE: Broken detailed Collectd charts

Hi

I installed the community edition at the time of the split and have come across an issue with the detailed charts.

When I click on the Collectd tab I see the various charts as expected. See the attached screenshot.

However, when I then click on one of the charts to see more detail, I get the broken image icon.

I would expect to see something like the following:

I am doing something wrong, or is this a bug?

Thanks, Frank