BPMN21 — message and error ref in tOperation does not define the correct type name

In Table 8.66, the spec says the inMessageRef and outMessageRef should be type of Message, however, in the xml schema below (table 8.68), the element type of inMessageRef and outMessageRef is a QName, not Message. similar issue happens on errorRef as well. table 8.66 says errorRef type should be Error, but the schema defines its type to a QName.