The ConceptMap2.group.element.target.dependsOn.value[x] element allows the 'code' data type to be chosen. When present as a code (valueCode) in a ConceptMap resource, it is then unclear which coding system the code was taken from nor the version of this coding system. 

The issues applies to both of the following elements:

ConceptMap2.group.element.target.dependsOn.value[x] 

ConceptMap2.group.element.target.product.value[x]{}

The ConceptMap2.group.element.target.dependsOn.property ** uri ** value associated with the valueCode may provide a hint about what the coding system is (or complete details if the URI is a URL which can be publicly accessed) this is insufficient as the property identifier may be unreliable or meaningless to recipients of the concept map.

The proposed resolution to this issue to remove 'code' as an acceptable choice datatype for the above elements. That way, when the value is a code, the element can be represented using the Coding datatype which supports assertion of both the coding system and the coding system version.