Right. Absolute prosecutorial immunity applies in all cases where the conduct is within a prosecutorial function. That is narrower than all official acts and explains almost all deviations from absolute immunity. (This is why I always advised prosecutors they have no absolute immunity for investigating, like advising on search warrants.). The CA never examined or discussed this important issue.
Of course I’m aware this is a civil case. I don’t know of any court that applied different standards, at least in the last 120 years or so.