FSM says:
There is supposed to be no pressure transmitted to the front slave until you exceed some amount. There may be some amount of intentional leakage through the Metering valve, not sure.Metering valve
This valve prevents the brake fluid pressure that is transmitted to the right front brake caliper from increasing
until the pressure exceeds a set level. Only the rear brake caliper is operated when there is
an extremely low amount of brake pedal input.