\linebylinepar bug report

\documentclass{article}

\begin{document}

\makeatletter
\def\linebyline#1 {%
\ifx\!#1\else
\setbox\z@\vbox{%
  \noindent\unhbox\tw@\unskip\unskip\unpenalty\sporindent#1}%
\let\sporindent\space
\ifdim\ht\z@>\baselineskip
\setbox\z@\vbox{%
\unvbox\z@
\global\setbox1\lastbox
\unskip\unpenalty\unskip\unpenalty
\global\setbox\thr@@\lastbox
}%
\hbox to \hsize{\unhbox\thr@@\unskip\unskip\unpenalty}%
\else
\setbox\z@\vbox{%
\unvbox\z@
\global\setbox\@ne\lastbox
}%
\fi
\setbox\tw@\box\@ne
\expandafter\linebyline
\fi}

\def\linebylinepar#1{{%
\par
\finalhyphendemerits\z@
\clubpenalty\z@
\widowpenalty\z@
\def\sporindent{\hskip\parindent}%
\setbox\tw@\hbox{}%
\@firstofone{\expandafter\linebyline#1} \! \relax
\box\tw@
\par}}
\makeatother

\hsize137pt
\hrule width\hsize
\parindent0pt\relax

\linebylinepar{meg\-szent\-s\'eg\-te\-le\-n\'it\-he\-tet\-len\-s\'e\-ges\-ke\-d\'e\-se\-i\-tek\-\'ert,
    au\-t\'o\-busz-\'al\-lo\-m\'as  % BUG: This word is missing.
    meg\-szent\-s\'eg\-te\-le\-n\'it\-he\-tet\-len\-s\'e\-ges\-ke\-d\'e\-se\-i\-tek\-\'ert}

\end{document}