Is this handled automatically somehow or should I have a scheduled job that deletes these periodically? I suppose keeping them for audit purposes makes sense but revocation does a hard delete so I don't think that's the intent of this table/entity.
I don't know if the EF implementation of persistent grants comes with a scheduled job, but that should be easy to verify by looking at what EF creates. We are using a different ORM to manage our grants table, so in that case yes - we would need to create a scheduled job to clean up that table.