ADuM5401 and Tri-State Input

I am using the CN-0336-EVAL board which has an AD7091R adc and a ADuM5401.  I'm having trouble with the MISO/SDATA being pulled low when the device is not selected.  It should go to high impedance after clocking the data out.  I was wondering, since the SDATA line goes to Vid on the ADuM5401 which outputs on Vod to my microcontroller, what does the ADuM5401 do with a high impedance input.  Does it output low on the Vod pin when the Vid pin is high impedance?  I have more than one device hooked to the SPI bus and it would be nice if the MISO/SDATA would get released.

Thanks for your help.