grouper log config should not produce error

in 2.5.50 I get the following message on startup:
log4j.properties read from: /opt/grouper/grouperWebapp/WEB-INF/classes/log4j.properties
Grouper warning, it is detected that you are logging edu.internet2.middleware.grouper as ERROR and not WARN level. It is recommended to log at at least WARN level in log4j.properties
Grouper is logging to file: /tmp/logpipe, at min level ERROR for package: edu.internet2.middleware.grouper, based on log4j.properties
I am not overriding log4j.properties - seems like this should be properly config'd as default.