QTabWidget: QComboBox item list position & background application visible

Preconditions:

Application includes QTabWidget. Tab includes one QCombobox at bottom of the tab screen area.
Application is on portrait mode. Split view is open.

Test steps:
1. Tap the small arrow icon on QComboBox.

Expected result:
Item list is opened.

Actual result:
Item list is opened but the position is not correct (only first two items are fully visible, third item is displayed only half and last item is not visible at all). Background application is visible between the item list and QComboBox.

• Note: this can only be reproduced when item list is opened for the first time. If opened second time, its position is ok & no background application visible.