Hello John
I suspect that this is an OMSA issue. Is OMSA installed on all of the servers? Do the servers that are not reporting host names correctly have anything in common, like the same OS or an OS that is not fully compatible with OMSA? Also, check out pages 85 and 86 in the CMC guide and make sure the host names meet the naming conventions of the CMC:
http://support.dell.com/support/edocs/SOFTWARE/smdrac3/cmc/cmc4_2/en/ug/pdf/cmcug_en.pdf