If two appenders within a joran configuration use the same name joran does not abort with an error. This may lead to not working system.

An example that actually happend:
An appender configuration for a RollingFileAppender with a FixedWindowRollingPolicy and a SizeBasedTriggeringPolicy was copied from one file into another, but the application included both files at once. Since all debug messages are to be written in this file it growed quite fast, but the system worked normally at first.
But when rolling occurs the file could not be renamed (two file handles to the same file), so the rename by copy fallback started. After copying the deletion still failed. So the current log file is still over the rolling limit. As you might already can imaging, this happens from now on for all log messages to be written and makes the system almost only doing copying files.

BTW.: The failure of the deletion of the current log file is also not reported as an error to the status manager.