Empty custom component library in Library area

In QDS 2.3, the components of a user custom library (https://doc.qt.io/qtdesignstudio/creator-qml-modules-with-plugins.html) are not shown (only the title bar is visible, with no component icons).
The import path seems to be recognised elsewhere though, and custom components can be added in the text editor with no errors shown, and then the properties can be graphically edited.

Prior to QDS 2.3 (e.g. QDS 2.2.2) there was no such problem.

The visual effect is the same as that reported in QDS-6056, so it may be related.