Updating model after some data insertion does not fetch extra fields

Hello friends,

I have been facing an issue that I have some entries in a collection. Later I added some extra fields. When I fetch items from collection, the older entries do not show additional fields although those fields are visible in JSON preview in dashboard. I am using cockpit 2.2.2
This is the case when the extra fields in older entries are kept blank, thus expected to be null in response.

Kindly suggest any possible solutions.

Best regards,