getting-started-tutorial | Official Bonita getting started solution

I followed the Bugtracker tutorial on the Uno Platform page

For some reason even simple text boxes don't seem to get rendered correctly on the Skia.Gtk backend. This is what the final example is supposed to look like:

Here's what I see with Skia.Gtk:

The description box is supposed to contain some text and label on the slider isn't showing either.

I get no pertinent warnings or errors, which makes it difficult to pin down the source of the problem. I've run the sample on WSL (running Ubuntu 18.04) as well as a real Debian buster machine. Reassuring is that the GUI renders the same on both.