Added CEM to existing APM 10.5.2.
Enabled Servlet Header Decorator with introscope.agent.decorator.enabled=true
GUID is included in the response, but the value of GUID is always 0
Upon viewing transaction traces in the Investigator, it appears that all traces (at least for the agents in question) have a GUID value of 0, causing all traces to be correlated with all other traces.