Incorrect width for elements (until resize)

Hi,

We're trying to port our Qt application from Qt 6.2.4 to Qt 6.4.3. However, even if it's not a major version change (Qt 5 to Qt 6), we observe some big changes (in the video pipeline, webengine and position of some elements).

The application is quite complex, but for the positioning, we successfully got a reproducible scenario. The scenario contains 2 QML objects, One defining a small interface with some button, the second is the button itself.

Then, we launch the application with Qt 6.4.3 and Qt 6.2.3. The result is pretty different, because buttons got a width of 0 (even if if should be different).

Note: any resize event on Qt 6.4.3 fix the view, but the initial state seems weird.
Note2: 2 screenshots are attached for both result. Used QML is the same on 6.4.3 and 6.2.4

Regards,