The Present_Value property of a Multistate Object may not have the value zero. This is specified in the BACnet specification. For example in paragraph 12.20.4 Present_Value of the 2008 Spec.
“The Present_Value property shall always have a value greater than zero.”
Gateways often boot with all data set to zero and may report this invalid state until the data has been updated using the Non-Bacnet data.