I am working on a problem with packages not refreshing their snapshots since last week  and today we have made a break thru: the root cause of the issue is a change of OwnerNSGuid that happened on the server coresettings.config during a SQL authentication change.
We don't know exactly how it happened but the change causes packages that do not match the coresetting OwnerNSGuid to not refreshed.
Note that vThisNS was not changed on the database.
Here are a few SQL query that we used int he tourbleshooting process:
select ownernsguid, count (*) from RM_ResourceSoftware_Package group by OwnerNSGuid
select ownernsguid, count (*) from Item group by OwnerNSGuid
Running the first query returned 3 different guids. Apparently the SMP migration created legacy packages under the 6.x OwnerNSGuid.
Now, we are planning to revert the OwnerNSGuid back to the original entry, still present in vThisNS. I'll post results back here when available...