DailyRollingAppender doing strange things with log4j-1.2.14

I'm noticying right now the following situation

-rw-r--r--  1  311170 Jul 16 14:00 name.log

-rw-r--r--  1  455880 Jul 16 14:00 name.log.2008-07-15

 What you should see is that today's log is actively overwriting yesterday's
rolled log.

So yesterdays log is history as it's been overwritten.

Can anybody explain this behaviour and whether a newer version corrects this
problem?