After upgrading to CA Identity Manager 14.3 CP 1 there appears to be a change in behaviour from the previous build (14.3 GA) when using the bulk task feature.
Release : 14.3
Component : CA IDENTITY SUITE (VIRTUAL APPLIANCE)
An issue was identified in 14.3 GA where too many results were returned. As part of performance improvements "does not equal" was corrected to NOT return null values as well as some wildcard values (*). This is designed to stop "runaway" queries from trying to fetch the entire dataset where values had not been defined and consuming a large amount of system resources.
This has been corrected in 14.3 CP1\2.