The child window does not get the style of the parent in the attached style properties example (QQuickAttachedPropertyPropagator)

MacOS 14.2.1 / Linux Ubuntu 22.04

Qt Creator 12.0.1

Qt 6.7.0-beta2

Steps to reproduce:

1. Run https://doc.qt.io/qt-6/qtquickcontrols-attachedstyleproperties-example.html 
2. Click the open window button
3. Change the mode to Dark. 

Expected: The child window should get the style from a parent as it is on Qt 6.6.1.

Actual: The child window does not change its style. See the attached video for reference. 

Reproducibility:  100%
 

NOTE: The issue is not reproducible on Qt 6.5.4 and 6.6.1