setChecked(false); does not work with QPushButton

I have some QPushButton, with setCheckable(true), I can do
button.setChecked(true);
The button is checked now.

After some time I call
button.setChecked(false);
But it has no effect!
Button is checked always!

i need to do this:
button.setCheckable(false);
button.setCheckable(true);
now button is uncheked.

Why??

you have some design error in your code, but with out seeing your code, we can't tell you where it is.