Nested attributes are not shown through search api

Steps to reproduce:

Create attached slb-wks-GenericDocumentArtefact.json schema with nested attribute and create a storage record.

Expected: All the attributes mentioned in the schema are all shown up and searchable through search API, including the nested attributes

Actual: Some the nested attributes are missing when querying the record through search api

Nested attributes such as data.classification.concept-tags, data.classification.taxnodes etc are missing

Also some of the attributes are being flattened is that expected?