Any use of IArchetypeQuery result paging without an ORDER BY on a unique column can result in non-deterministic results.
i.e, the same IMObjects may be returned more than once, or not at all.
Typically, we either:
1. don't include an ORDER BY clause for paged results; or
2. include an ORDER BY clause on a non-unique column (e.g, on act startTime, customer name)
In these cases, an ORDER BY on the uid should be used.
This applies to both ArchetypeQuery and NamedQuery instances.