NPRD-2011 data for a circuit card assembly shows many Number Failed entries in the case of an AUA environment. However, for the same circuit card in an ARW environment (on the same NPRD page) there are no Number Failed entries for over roughly the same time period as in the AUA case. The same applies for circuit card assemblies in a N (naval) environment. I’ve noticed the same situation for numerous other parts in addition to circuit cards.

Is there any explanation for this seemingly inconsistent circumstance?