References
This issue has been reported by French IGN.
http://joinup.ec.europa.eu/mailman/archives/dcat_application_profile-geo/2015-August/000195.html
Explanation
Draft 6 of the GeoDCAT-AP specification, in its Annex II.8, proposes to have different mappings for free keyword depending on if the resource is a dataset or a service. Same remark for keywords with a controlled vocabulary. French IGN questions whether this is a good practice.
Comments
See response by Andrea
http://joinup.ec.europa.eu/mailman/archives/dcat_application_profile-geo/2015-September/000215.html
"DCAT-AP does not distinguish between datasets and series, so they are
both typed with class dcat:Dataset - i.e., in the DCAT-AP context, a
series is considered a dataset. So, the mappings defined for keywords
apply to both datasets and series."
GeoDCAT-AP Draft 7 clarifies this point.