Any attempt to change Mail session after it was created fails

Steps to Reproduce: In jboss-cli
1. Create new session
/subsystem=mail/mail-session=mysession/:add(jndi-name="java:/musession")

result:

{"outcome" => "success"}

2. Check created resource
/subsystem=mail/mail-session=mysession/:read-resource

result:
{
"outcome" => "success",
"result" =>

{ "custom" => undefined, "debug" => false, "from" => undefined, "jndi-name" => "java:/mysession", "server" => undefined }

}

3. Try to change some attribute (e.g. jndi)
/subsystem=mail/mail-session=mysession/:write-attribute(name=jndi-name,value="java:/mailsession")

result:
{
"outcome" => "failed",
"failure-description" => "JBAS014749: Operation handler failed: null",
"rolled-back" => true
}

expected result:

{
"outcome" => "success",
"response-headers" =>

{ "operation-requires-reload" => true, "process-state" => "reload-required" }

}

Additional:

The debug attribute can be changed exactly once and only to true. Once it is turned on it cannot be changed again like the rest.