ADG 811 YRUZ Switch not high impedant in open mode

Following test application: GND connected to 0V, VDD connected to +3V, NIC not connected, IN1, IN2, IN3, IN4 conected to +3V --> all switches should be open (>>10E10 Ohm). However between D and S (of all switches) there is a resistance of about 6 kohm (testing voltage 2 Volt. In closed mode (IN at 0V) all is fine --> Ron=0,5 Ohm.

Any suggestion?