Even though LOG4J2-3080 <https://issues.apache.org/jira/browse/LOG4J2-3080> appears like a JsonTemplateLayout problem, it is more related with Log4j 1 Category implementation always using either MapMessage or ObjectMessage rather than SimpleMessage whenever possible. I have enhanced Category#maybeLog() accordingly to check for String and CharSequence types too. I would appreciate it if one can review GitHub PR #504 <https://github.com/apache/logging-log4j2/pull/504>.
