logger filter-spec does not suppress exceptions in the log in EAP 6

Issue

A web-application is running on JBoss, in the case of an exception it should be written to a file using a file-handler, however, not every exception should be saved. For this I wanted to use the filter-spec of the file-handlers.

<file-handler name="EXCEPTION-FILE" autoflush="true">
        <level name="ERROR"></level>
        <filter-spec value="not(match("MyCustomException"))"></filter>
                <formatter>
                        <pattern-formatter pattern="%d %-5p [%c] (%t) %s%E%n"></pattern>
                </formatter>
        <file path="/var/log/jboss/mylogfile.log"></file>
        <append value="true"></append>
</file-handler>

This configuration should filter out all MyCustomException, however they are still being written to the file.