Error. Null Reference Exception

[nuggen6]

Hi!
I'm getting the following error:

Object reference not set to an instance of an object.
at Xbim.COBieLite.XbimAttributedObject.GetAttributeValue(IIfcPropertyBoundedValue ifcPropertyBoundedValue)
at Xbim.COBieLite.XbimAttributedObject.ConvertToAttributeType(IIfcProperty ifcProperty)
at Xbim.COBieLite.CoBieLiteHelper.GetAttributes(IIfcObjectDefinition ifcObjectDefinition)
at Xbim.COBieLite.FacilityType..ctor(IIfcBuilding ifcBuilding, CoBieLiteHelper helper)
at Xbim.COBieLite.CoBieLiteHelper.d__81.MoveNext()

Running this code. I'm trying to save as json.

var helper = new CoBieLiteHelper(model);
var facility = helper.GetFacilities()?.FirstOrDefault();

Sample.zip

Thanks!
nuggen