A Toggle that belongs to a ToggleGroup should be able to be set to isOn = false via script. Right now, doing so has no effect, even though the field is public. The result would be that a ToggleGroup could have no active Toggle.
At the very least, it's inconsistent that a ToggleGroup will permit its Toggles to all be isOn == false at Start but not if one is enabled and then disabled again during runtime.
At the very least, it's inconsistent that a ToggleGroup will permit its Toggles to all be isOn == false at Start but not if one is enabled and then disabled again during runtime.