Recurring "missing parents" and "orphaned objects" in NSS verify log.

When running a NSS /PoolVerify on a Pool a lot of "missing parents" and "orphaned objects" appear in the verify log.

----- Volume Problem Report ------
Lost Data Blocks...................0
Files With Lost Data...............0
Duplicate Object IDs...............0
Object ID range errors.............0
Missing Name Entries...............0
Extra Name Entries.................0
Sys Objects Name Entries...........0
Name Entries W/O IDs...............0
Missing Salvage Entries............0
Unreadable Objects.................0
Missing Parents in NT.............43
Orphaned Objects..................43

Currently there is only a temporally solution to this issue:

Run a NSS /PoolRebuild on the affected Pool.

This however will not permanent remove this issue, the "Orphaned Objects" will return after some time.
Another NSS /PoolRebuild is needed at that time.