Technically you should still amend federal if it changes any of the lines on the 1040 even if the refund amount doesn't change.
CA may get confused if you file a return with information from the 1098s that isn't reflected on your federal return. I know my state wants to see a copy of my federal return whenever I file a state return, I think CA is probably the same in that regard.
What kind of 1098s were they, and how much were the amounts, and why does it change your CA refund but not your federal?