\version "2.24.2"

% Melody bar in alternative 2 out of sync after tie into alternative 1.
% "DD" should be the last note in bar 4, not the first in partial bar 5!
% If the alternative 2 starts with "r2" this error shows up as well.
% If the alternative 2 starts with "r4" this error does not show up.

\relative c'' {
  \time 4/4
  \repeat volta 2 {
    g1~ |
    \alternative {
      {
        g4 g2. |
      }
      {
        g4 r2 r4 |
      }
    }
  }
  g4 g4 g4 g4 |
}

\addlyrics {
  \lyricmode {
    \repeat volta 2 {
      A __
    }
    \alternative {
      {
        B |
      }
      {
        C |
      }
    }
    DA DB DC DD |
  }
}