Why the value wait-time of the EJB bean statistic is not calculated

Issue

• We have statistics enabled using the following entry inside the profile as following:

<subsystem xmlns="urn:jboss:domain:ejb3:1.4">
   .
   .
    <statistics enabled="true"/>

• We have other values, such as "executionTime" and "invocations", but wait time is always 0.

Example:

/deployment=Stateful_EJB_Ear.ear/subdeployment=Stateful_ejb.jar/subsystem=ejb3/stateful-session-bean=AccountBean:read-resource(include-runtime=true)
{
    "outcome" => "success",
    "result" => {
        "cache-size" => 2,
        "component-class-name" => "AccountBean",
        "declared-roles" => [],
        "execution-time" => 0L,
        "invocations" => 0L,
        "methods" => {},
        "passivated-count" => 0,
        "peak-concurrent-invocations" => 0L,
        "run-as-role" => undefined,
        "security-domain" => "other",
        "total-size" => 2,
        "wait-time" => 0L
    }
}

• How to get the correct "wait-time" ?