probably you could also try this solution, just assign a new Context to the 2nd combo box:
combobox1.DataSource = results;
combobox1.DisplayMember = "DisplayValue";
combobox1.ValueMember = "Value";
combobox2.BindingContext = new BindingContext(); //create a new context
combobox2.DataSource = results;
combobox2.DisplayMember = "DisplayValue";
combobox2.ValueMember = "Value";
Thank you