Widget showMaximized() is not working as expected for a widget having very small height

If for a widget, height is reduced to a small value in Form.ui, showMaximized() does not work as expected. It goes into a broken maximize state positioned in the top left corner with no resize options. Clicking Maximize centres the app and allows for restore, clicking Maximize again then correctly maximizes.
Please find the attached sample, where you can see height is changed in Form.ui, say 700.
If you increase height to say, 2000, showMaximized() will work fine,

showMaximized() should not be depended on height specified in the form.