Issue with \set chordChanges = ##t

[Kuredant]

Hello,

I have some issues when using \set chordChanges = ##t as described in 
the "Showing chords at changes" of the documentation 
(https://lilypond.org/doc/v2.23/Documentation/notation/displaying-chords).

* When using \set chordChanges = ##t inside \new ChordNames, the chord 
names are moved below the staff, and are still repeated even if there is 
no change (see the attachment "chord-change-example-with-changes.pdf").

* When using \set chordChanges = ##t inside \new ChordNames, with 
#ly:one-page-breaking, the generated PDF can't be opened (see the 
attachment "chord-change-example-with-changes-one-page-breaking.pdf").


Here is the code I used, compiled with LilyPond 2.23:

\version "2.20.0"

\header {
  tagline = ##f
}

\paper {
  indent = 0\mm
}

song = \relative c, {
  \repeat unfold 16 a4 |
  \break
  \repeat unfold 8 d |
  \repeat unfold 8 a |
  \break
  \repeat unfold 4 e |
  \repeat unfold 4 d |
  \repeat unfold 8 a' |
}

\score {
  \new StaffGroup <<
    \new ChordNames {
      \set chordChanges = ##t
      \chords {
        a1:m7 q q q
        d:m7 q a:m7 q
        e:m7 d:m7 a:m7 q
      }
    }

    \new Staff {
      \clef "bass_8"
      \time 4/4
      \song
    }
  >>

  \layout {
    \context {
      \Score
      \remove "Bar_number_engraver"
    }
  }
}

chord-change-example-no-changes.pdf
Description: Adobe PDF document

chord-change-example-with-changes.pdf
Description: Adobe PDF document

chord-change-example-with-changes-one-page-breaking.pdf
Description: Adobe PDF document