I'm working on the CMR client for dataset level metadata at NSIDC, we are in the process of testing our records using the REST API (UAT) and we ran into a weird issue now submitted as a bug here: - CMR-2927Getting issue details... STATUS
Basically we had a document that validated against the schema and yet we got an error when we tried to validate it using the API, the apparent reason was that there are some extra items being used, in this case the <gmd:referenceSystemInfo> tag, which is not mandatory according to the schema. My question would be how can we get a better idea of the actual API requirements? is the schema enough? maybe the API should return the full error stacktrace and/or the documentation needs to be extended?