We have a rollup field that is finding the last date of activity and showing it on the Account. It seems to be working for 90% of all the accounts in the system but the other 10% just doesn't. I can force the recalculation and it works just fine. If I put in an activity and then close it out, then it seems to start working again. The status (1) and update time (today) all seem to be fine. All the other rollups seem to be fine through the system.
I'm just at a loss here and any help would be appreciated.