There is an unwanted behavior with \accidentalStyle piano and a PianoStaff. To illustrate this, imagine you have a note with an accidental in the bass clef tied across two measures, and in the treble clef, in the second measure, you have this same note (can be a different octave) repeated. The second repeated note will have an unneeded accidental. This is much easier to see than explain, so here is a MWE with a PNG attached.
%%% \version "2.23.3" \language "english" rightHand = \relative c' { fs4 fs fs fs | fs4 fs fs fs | } leftHand = \relative c { \clef bass fs1 ~ | fs1 | } \new PianoStaff << \accidentalStyle piano \new Staff \rightHand \new Staff \leftHand >> %%% This looks like a bug, but I want to run it past y'all. -- Knute Snortum