modifyTimestamp does not always update

[Jani Salonen <jani.salonen@eficode.fi>]

Seems that modifyTimestamp of groupOfUniqueNames does not always update
as it should. We have one application that updates uniqueMembers of
groupOfUniqueNames groups (we have about 30000 groups, from 5 to 1000
members each). Another application syncs its sql database based on
groupOfUniqueNames member's once an hour, and for speeding things up, 
that another application first looks from modifyTimeStamp if group has
changed within last hour, and if so, it will be synced. But here is the
problem: another application's database does not always sync because
modifyTimestamp does not always update for some group.

Unfortunately this happens quite rarely and I cannot provide exact
instructions how to reproduce this, I was not able to find any pattern
either. If anyone has any ideas/experiments what is wrong/how to fix
this, they are most welcome.

Thanks, Jani Salonen