we cant be shown everything.we could then also ask if neo ever went to the toilet.some things are obvious and not relevant.who knows how many yrs passed between neo defeating smith in m1, and meeting the dude in m2.lets leave the subject coz l dont think its of any relevance except confusing for no reason at all.
i think Seraph wasnt around in M1 as the Oracle was safe - she was in her house with the orphans under no immediate threat.
In M2 shes not in her house and under threat so her protector is with her.
It is quite logical that seraph was her protector in M1 but he wasnt needed and would have been an extra unnecessary character (at that time)