Schema validation does not work with un-defining a namespace

I have added a test for this:
test/rbkt/zorba/schemas/any
For example, in the query:
validate {
  <any:elem>
    <any_elem xmlns:any=""/>
  </any:elem>
}
any_elem, is not in the any namespace anymore. Schema validation fails (which is wrong) if elem has the following type:

 <xs:element name="elem">
    <xs:complexType>
      <xs:sequence>
        <xs:any namespace="##other" processContents="skip" minOccurs="0" maxOccurs="unbounded"/>
      </xs:sequence>
    </xs:complexType>
  </xs:element>

The above type allows any element to be a child of "elem" except the elements in the schema's target namespace.