[Samba] Why %M makes two log files?

[Adam Tauno Williams]

I use log.%M to get per client logs.  This works but I always end up
with -

[root at littleboy root]# cd /var/log/samba
[root at littleboy samba]# ls -l log.pc01699
-rw-r--r--    1 root     root      2642617 Nov 12 07:30 log.pc01699
[root at littleboy samba]# host pc01699
pc01699.morrison.iserv.net has address 192.168.19.191
[root at littleboy samba]# host 192.168.19.191
191.19.168.192.in-addr.arpa domain name pointer
PC01699.morrison.iserv.net.
[root at littleboy samba]# ls -l log.192.168.19.191
-rw-r--r--    1 root     root            0 Oct 15 07:26
log.192.168.19.191
[root at littleboy samba]#

DNS works both ways,  but I always get a log.{IP NUMBER} file as well as
log.{MACHINE NAME}.  The log.{IP NUMBER} files are always zero sized.

Is this a bug or a misconfiguration of something (if so, pointers
appreciated)?