Updating font size in QML editor doesn't work or reverts to default size when unit is changed

When I update the font size for the Text component in the designer, and press enter, or otherwise, it doesn't automatically update the font size in the preview window. If I change the size unit from points to pixels, the font size reverts to something small, such as 8 pixels.

It does successfully update if I close the designer tab, change the "font.pointSize" property, and then re-open the designer; the font size looks different.