[REG]: 6.7.0 full-screen app displays background window (or splash-screen) graphics at top/bottom during multiwindow split display

Beginning with Qt6.7.0 (didn't happen at first, for triage, the regression was introduced during one of the betas, I recall) and continuing into 6.8.0 "dev", when a Qt app which automatically displays in "full screen" mode when horizontal is also displayed using Android "Multi window" feature - displays traces of the background splash screen when the mobile device is rotated into "landscape" mode.

The same app normally displays fine using this Android 11, 12, 13, 14 "Multi window" feature that allows to apps to display simultaneously on one mobile screen. That is, for Qt5.15, 6.2.X, 6.3.X, 6.4.X, 6.5.X, 6.6.X it was not a problem. Even early beta and dev releases of 6.7 worked fine. Sometime during the 6.7.0 release, this regression was introduced, looking like:

A work-around is that turning off "full-screen" gets rid of the splash-screen background seen at top/bottom of left-hand-side split:

After deselecting "full screen" background splashscreen no longer showing:

After menu popped down from above workaround, no splashscreen showing:

In 6.7.0, note that when the multi-window split is setup in portrait mode on mobile, the splashscreen isn't showing (and app is automatically not in "full screen" mode that seems to trigger the problem, when in portrait mode):

6.6.3 and prior don't behave that way when in landscape mode and using android multi-window split:

And in portrait mode after setting up the multi-window split , 6.6.3 displays normally.