Inconsistency in data load from cube to cube

Hi ,

I am trying to perform a full load from source cube to the target cube. target cube which is a copy of the source cube. I have used a full load DTP without any filters applied. however , I still see some inconsistency in  data . My source cube has 69k records, whereas my target cube has only 9k records loaded after a full load.Also only the records which have null WBS values are being populated in the target cube. Has anyone experienced this scenario while working on BW. Could someone suggest of what might have been the issue behind only NULL WBS's being extracted into the target.

thanks,

Sneha