Do you mean contextCSNs?
No. ContextCSN is up to date. But some entries have old entryCSN compared
to the master.
I haven't been able to track the cause nor see anything in the log to
indicate the problem. However, we have had slapd become non-responsive
due to IO blocking on logging. Could this cause syncrepl to miss
updating the entries? Has anyone seen this behaviour?
If slapd gets locked up, hard to say what the side effects could be.
Do you have stats+sync logging enabled on all of the systems?
I do have stats and sync enabled.