This sounds as if the entities that are returned through OData all have the same key.
The OData models manages its data in a map where the actual record is mapped to the key. If there is a second record with the same key, it will overwrite the data of the first record, and so on. Eventually, there might only be on distinct key, thus, the table would display only that one record.
To verify, look at the OData metadata and find out that is key of the entity that you're displaying. Then, look into the response with e.g. the Chrome DevTools and check whether the keys that are returned from the backend are unique. They probably aren't 
- Max