The problem appears in Log4j 2.0-beta7 and in revision 1497930. I
attached a one-line patch that fixes it.
In method "FlumePersistentManager.createManager", the loop over
"properties.entrySet()" should break immediately after "key" is set
the first time to "entry.getValue()". I don't think "key" is set a
second time (and therefore all future iterations are not useful), but
if it is, then there is a problem in the implementation: when the loop
exits, "key" would be set to the last value of "entry.getValue()" that
meets some condition; however "properties.entrySet()" is a Set and
therefore the order of iterating it is non-deterministic, i.e., the
implementation should not rely on which the "last value" is.