To reproduce:
- Start the attached project. 
- Collapse and then expand the group.
- The label should remain hidden.

Workaround:
bool labelVisiable = false;
private void TxtIdNro_VisibleChanged(object sender, EventArgs e)
{
    if (txtIdNro.Visible && !labelVisiable)
    {
        txtIdNro.Visible = false;
    }
}