Hi,
this is an unfortunate limitation in how soapUI generates XML from REST (JSON) responses - it will use the endpoint of the service as the namespace, which results in what you are seeing - ie XPath-assertions that are tied to namespaces will fail when switching endpoints. Unfortunately for the MCA assertion there is currently no workaround - you would have to use standard XPath assertions instead which would allow you to either create namespace-agnostic XPath statements or use property-expansion for the namespace.
Hope this helps!
/Ole
SmartBear Software
