sql server 2008 R2 deferred updates replication

I have a transactional replication of a table on a sql server 2008 R2 server that recently is converting update commands into delete+insert command (deferred updates). The primary key is never updated. There is no unique index on the published table. The sql server portfolio on subscriptions show all rows that were updated on the published table are deleted and then inserted. I'm not sure if the deferred updates take place on publishing server or not.

Thanks,

Bahram