Running on 2.4.39 centos 6.4 in MMR setup ( 4 servers ).  001 is the provider that was being written to at the time. The log is from 001.  Could you advise whether my understanding of the log  is correct? 

synrepl consumer on serverID=001 is polling syncrepl provider on serverID=001 and 003 and gets the CSN that is older that its own.  We were doing a lot of writes during this time and there were cmp -1  104480 or  simiar entries in the log. I had similar issue in the past while running 2.4.37 and it crashed slapd at that time but it didnt this time.  The CSN were all synced at the end without any issue. 

Could you advise what could be causing this? 

Oct  8 20:36:50 servername slapd[58097]: srs csn 20141008181030.452659Z#000000#001#000000

Oct  8 20:36:50 servername slapd[58097]: log csn 20140723214017.586869Z#000000#001#000000

Oct  8 20:36:50 servername slapd[58097]: cmp -1, too old

Oct  8 20:36:50 servername slapd[58097]: log csn 20140723214017.847644Z#000000#001#000000

Oct  8 20:36:50 servername slapd[58097]: cmp -1, too old

Oct  8 20:36:50 servername slapd[58097]: log csn 20140723214122.276227Z#000000#001#000000

Oct  8 20:36:50 servername slapd[58097]: cmp -1, too old

Oct  8 20:36:50 servername slapd[58097]: log csn 20140723214515.997173Z#000000#001#000000

Oct  8 20:36:50 servername slapd[58097]: cmp -1, too old

Oct  8 20:36:50 servername slapd[58097]: log csn 20140723214734.650752Z#000000#001#000000

Oct  8 20:36:50 servername slapd[58097]: log csn 20140723220152.569135Z#000000#003#000000

Oct  8 20:36:50 servername slapd[58097]: cmp -1, too old

Oct  8 20:36:50 servername slapd[58097]: log csn 20140723220328.184724Z#000000#001#000000

Oct  8 20:36:50 servername slapd[58097]: cmp -1, too old

Oct  8 20:36:50 servername slapd[58097]: log csn 20140723222016.864642Z#000000#001#000000

Oct  8 20:36:50 servername slapd[58097]: cmp -1, too old

Oct  8 20:36:50 servername slapd[58097]: log csn 20140723232832.307038Z#000000#003#000000

Oct  8 20:36:50 servername slapd[58097]: cmp -1, too old

Oct  8 20:36:50 servername slapd[58097]: log csn 20140723232958.001298Z#000000#003#000000