That's in the recording, i.e. bad mastering, re-mastering.
And those are quite few and most importantly very tolerable.
This was the very 1st track i played upon receipt of the Fan (for sibilance). Turned out more than acceptable.
Next was
To try out the Mids character & tonality, i.e. is it fluid, dry, etc & is it rich, warm or neutral?
I use this track to detect sibilance: