Simscape per unit Voltage calculation

Why does the Current and Voltage Sensor (Three-Phase) divide by sqrt(2) in order to calculate the per unit value of the voltage?

Ex: for V = 866.5 kV (RMS phase-phase) with Vbase = 735 kV (RMS phase-phase), the per unit value of V should be Vpu = V/Vbase = 866.5/735 = 1.18 pu. However, the Current and Voltage Sensor (Three-Phase) ouputs Vpu = 0.8336, which is (V/Vbase)/sqrt(2).

See the attached Simulink model.