I draw you attention to Annex A to IHO Circular Letter 67/2013 of 21 November 2013 which mentions possible inconsistencies between publications B-6 and S-32 and suggests that the HDWG should take the matter into its own hand.
Here are some relevant excerpts:
"As indicated on pages 2-9 in publication B-6, the definitions are not always in keeping with those in S-32....France would prefer that when a definitions already exists in S-32, that this latter be used as a reference...etc." Comments by IHB: Definitions contained in B-6 have been developed by SCUFN members who are specialists in marine geomorphology. As a result, they appropriately support SCUFN's work of naming undersea features. The IHO HDWG, tasked to maintain S-32, may wish to propose the inclusion in S-32 of B-6 definitions, subject to them meeting the purpose of the IHO Hydrographic Dictionary.