Split view flashes when opened for QSpinBox

Preconditions:
Application includes QMainWindow with one QSpinBox that supports text input.
Application is on portrait mode.

Test steps:

1. tap the input field on QSpinBox
--> split view is opened.

Expected result:
Split view is opened without flashing.

Actual result:
Application menu flashes on small area of split view upper left corner when the split view is opened.