QML scene freezes if a Scene3D bool property is toggled

If the renderPolicy of a Scene3D component is set to OnDemand and the property hoverEnabled is toggled the whole 3d scene won't update anymore. Even the QML scene will stop updating unless a QML component triggers any update.

We noticed this behavior since Qt version 6.4.1, which introduced a change in the hoverEnabled property to request an update of the QuickItem.

The following was was mentioned in the release notes:

• ef6fe3e499 DA: ignore disabled HoverHandlers when delivering hover
  events
  Disabled hover handlers will no longer receive hover events, or block
  siblings from being hovered. 

To reproduce the bug I used the scene3d example and disabled the animations and enabled OnDemand rendering. To toggle the hoverEnabled property I used the top text label. Clicking on the text label the whole QML scene and 3d scene freezes, which means you can not interact with the 3d scene anymore until any QML scene update occurs, like e.g. moving the window or hovering a button.

I used the RivaTuner Statistics Server which is part of the MSI Afterburner application to display the current FPS counter and the current time inside the QML scene. When the freeze occurs the counter stops updating.

Additionally the scene3d example also allows to toggle the multisample property of the Scene3d via clicking on the bottom text label, which also leads to a freeze, but is reproducible with any Qt 6.x version (tested 6.3.1, 6.4.0, 6.4.1, 6.4.2).

For now we have to stick with Qt 6.4.0. Hopefully someone can resolve the issue.