Yes, the documents seem to be out of date?
There can be multiple entries for each ContentDocument. In the case of attachments (Lightning uses ContentDocument for attachments), there will be a record in the ContentDocumentLink for both the UserId and the record that is the Attachments Parent.
You can use a query similar to the below to find details of the attachments relating to an sObject. In this example a Case Id. *Note that the ContentDocumentLink object must be filtered with a where clause.
SELECT Id, LinkedEntityId, ContentDocumentId, Visibility, IsDeleted, ShareType,
ContentDocument.Title, ContentDocument.createdDate, ContentDocument.FileType
WHERE LinkedEntityId = '5000Y000999MQKTQA4'