Sounds like you’ve clicked on the “listen” button on SpitFish, which plays what’s being removed.
If the problem is whistling esses, those require surgical-precision, (SpitFish can’t do that).
Paul-L’s free DeEsser plugin is capable of dealing with those … Updated De-Clicker and new De-esser for speech - #37 by Trebor
TB Sibilance CM* is is a very good free DeEsser: IMO as good as $50 -$100 DeEsser plugins. (It won’t cure Herbert-level whistles though).
[* Windows & Mac]