QLabel padding not applied when unpolish, polished

[HyunYoung]

I define style sheet and test.py like below.

I expected the label's text padding change 10px -> 100px but its not applied. The background color changed to RED. I test color, font-size as well, but only 'padding' didn't applied after click the button.

Can anyone explain why only padding not applied in style sheet?

style

.QLabel[text="OK"]{
  background-color: rgb(0,255,0);
    color: rgb(255,250,250);
    font-size: 24pt;
    padding: 10px;
}

.QLabel[text="ERR"]{
  background-color: rgb(255,0,0);
    color: rgb(255,250,250);
    font-size: 24pt;
    padding: 100px;
}

test.py

from PySide6 import QtWidgets
from PySide6.QtCore import Qt


class MyWindow(QtWidgets.QWidget):
    def set_style(self):
        with open('./style', 'r') as f:
            self.setStyleSheet(f.read())

    def __init__(self):
        super().__init__()

        self.set_style()
        self.setupUi()

    def setupUi(self):
        self.label = QtWidgets.QLabel('OK', self)
        self.label.setAlignment(Qt.AlignCenter)
        self.button = QtWidgets.QPushButton('Button', self)

        vlayout = QtWidgets.QVBoxLayout(self)
        vlayout.setAlignment(Qt.AlignCenter)
        vlayout.addWidget(self.label)
        vlayout.addWidget(self.button)

        self.button.clicked.connect(self.btn_clicked)

        self.show()

    def btn_clicked(self, a):
        self.label.setText("ERR")
        self.label.style().unpolish(self.label)
        self.label.style().polish(self.label)
        self.update()


if __name__ == "__main__":
    app = QtWidgets.QApplication([])
    win = MyWindow()
    app.exec_()