QRadiobutton doesn't work as expected

I've got group of radiobuttons on a dialog and between them I've got a groupbox with another group of radiobutton. These inside a groupbox work as expected (C, D on attached screenshot)

these on dialog not. I may click on A and it will uncheck like if it is a checkbox. All have "autoExclusive" set to true. When I remove C and D from the groupbox A and B are working as expected - I cannot uncheck them all.