09:19:00,578 WARN  [org.wildfly.extension.messaging-activemq] (ServerService Thread Pool -- 18) WFLYMSGAMQ0101: Invalid value xa for transaction, legal values are [local, none, xa], default value is applied.

[standalone@localhost:9990 /] /subsystem=messaging-activemq/server=default/pooled-connection-factory=activemq-ra:write-attribute(name=transaction,value=xa)
09:31:21,542 WARN  [org.wildfly.extension.messaging-activemq] (management-handler-thread - 2) WFLYMSGAMQ0101: Invalid value xa for transaction, legal values are [local, none, xa], default value is applied.
{"outcome" => "success"}

[standalone@localhost:9990 /] /subsystem=messaging-activemq/server=default/pooled-connection-factory=activemq-ra:write-attribute(name=transaction,value=invalid)
09:33:52,278 WARN  [org.wildfly.extension.messaging-activemq] (management-handler-thread - 1) WFLYMSGAMQ0101: Invalid value invalid for transaction, legal values are [local, none, xa], default value is applied.
{"outcome" => "success"}

[standalone@localhost:9990 /]  /subsystem=messaging-activemq/server=default/pooled-connection-factory=activemq-ra:read-attribute(name=transaction)
{
    "outcome" => "success",
    "result" => "xa"
}

...
09:35:37,737 INFO  [org.jboss.as] (MSC service thread 1-2) WFLYSRV0049: WildFly Full 16.0.0.Final (WildFly Core 8.0.0.Final) starting
09:35:38,481 INFO  [org.wildfly.security] (ServerService Thread Pool -- 15) ELY00001: WildFly Elytron version 1.8.0.Final
09:35:38,688 WARN  [org.wildfly.extension.messaging-activemq] (Controller Boot Thread) WFLYMSGAMQ0101: Invalid value foo for transaction, legal values are ["local", "none", "xa"], default value is applied.
09:35:38,945 INFO  [org.jboss.as.controller.management-deprecated] (Controller Boot Thread) WFLYCTL0028: Attribute 'security-realm' in the resource at address '/core-service=management/management-interface=http-interface' is deprecated, and may be removed in a future version. See the attribute description in the output of the read-resource-description operation to learn more about the deprecation.
09:35:38,979 WARN  [org.wildfly.extension.messaging-activemq] (ServerService Thread Pool -- 7) WFLYMSGAMQ0101: Invalid value foo for transaction, legal values are [local, none, xa], default value is applied.
09:35:38,980 INFO  [org.jboss.as.controller.management-deprecated] (ServerService Thread Pool -- 38) WFLYCTL0028: Attribute 'security-realm' in the resource at address '/subsystem=undertow/server=default-server/https-listener=https' is deprecated, and may be removed in a future version. See the attribute description in the output of the read-resource-description operation to learn more about the deprecation.
...