Fullscreen toggle always true for some reason

I have a toggle UI for toggling fullscreen and in my UIManager script I have the following code

private void Start() {
    fullscreenToggle.onValueChanged.AddListener(delegate { OnFullscreenToggle(); });

public void OnFullscreenToggle() {
    OptionsData.fullscreen = fullscreenToggle.isOn;
    Screen.fullScreen = OptionsData.fullscreen;

OptionsData.fullscreen is toggled between true and false correctly however Screen.fullscreen is always true not matter what. I did previously set the Listener directly in the editor with the dynamic bool for the function but that didn’t work either and I have no idea why Screen.fullscreen is always true even if OptionsData.fullscreen is false.

Can someone please help me find the solution?

Had this same issue today.
Try reseting the player settings by going into build, player settings, and right clicking the little slider icon and hitting reset.