Bad pagebraks in longtable (empty table on second page)

Question

I have some strange problem with my longtables. In some tables there is a pagebreak after the last row and on the second page there is the table header printed again without following content. I use the patched longtable from How to make longtable respect \nopagebreak in the beginning?.

Here is a not really minimal example, which shows the problem in the second table:

\documentclass[open=any, a5paper, fontsize=9pt, DIV12]{scrbook}
%\usepackage[utf8x]{inputenc} only for pdflatex

\usepackage{etoolbox}
\usepackage{array}
\usepackage{longtable}
\usepackage{libertine}
\setcounter{secnumdepth}{-1}

\newcommand{\br}{\hfill\break}

\newif\ifnormalLT
\normalLTtrue

\makeatletter
\patchcmd {\LT@start}
      {\vfil\break}
      {\ifnormalLT\vfil\break\fi}
      {\typeout{Patching longtable succeeded!}}
      {\typeout{Patching longtable failed!}\ERROR}
\patchcmd {\LT@start}
      {\penalty\z@}
      {\ifnormalLT\penalty\z@\fi}
      {\typeout{Patching longtable succeeded!}}
      {\typeout{Patching longtable failed!}\ERROR}

\makeatother


\newenvironment{deklination}
{
\setlength{\extrarowheight}{.75ex}%
\normalLTfalse
\longtable{lp{3cm}p{3cm}p{3cm}}
&\textbf{Sg.}&\textbf{Du.}&\textbf{Pl.}\\
\endhead
}
{\endlongtable}

\usepackage{hyperref}

\begin{document}

\chapter{Lektion IX}

\section{Grammatik}

\subsection{Pronomen der zweiten Person svad, yuṣmad}

\begin{deklination}
\textbf{Nom.}&{svam}&{yuvām}&{yūvam}\\
\textbf{Akk.}&{svām},\br {svā}&{yuvām},\br {vām}&{yuṣmān},\br {vaḥ}\\
\textbf{Inst.}&{svayā}&{yuvābhyām}&{yuṣmābhiḥ}\\
\textbf{Dat.}&{tuhyam},\br {te} &{yuvābhyām},\br {vām}&{yuṣmabhyam},\br {vaḥ}\\
\textbf{Abl.}&{svat}&{yuvābhyām}&{yuṣmat}\\
\textbf{Gen.}&{tava},\br {te}&{yuvayoḥ},\br {vām}&{yuṣmākam},\br {vaḥ}\\
\textbf{Lok.}&{svayi}&{yuvayoḥ}&{yuṣmāsu}\\
\end{deklination}

\subsection{Pronomen der dritten Person tad – er, sie, es; jener, jene, jenes}
\subsubsection{Masculinum}

\begin{deklination}
\textbf{Nom.}&{saḥ}&{tau}&{te}\\
\textbf{Akk.}&{tam}&{tau}&{tān}\\
\textbf{Inst.}&{tena}&{tābhyām}&{taiḥ}\\
\textbf{Dat.}&{tasmai}&{tābhyām}&{tebhyaḥ}\\
\textbf{Abl.}&{tasmāt}&{tābhyām}&{tebhyaḥ}\\
\textbf{Gen.}&{tasya}&{tayoḥ}&{teṣām}\\
\textbf{Lok.}&{tasmin}&{tayoḥ}&{teṣu}\\%
\end{deklination}

\subsubsection{Femininum}
\begin{deklination}
\textbf{Nom.}&{sā}&{te}&{tāḥ}\\
\textbf{Akk.}&{tām}&{te}&{tāḥ}\\
\textbf{Inst.}&{tayā}&{tābhyām}&{tabhiḥ}\\
\textbf{Dat.}&{tasyai}&{tābhyām}&{tābhyaḥ}\\
\textbf{Abl.}&{tasyāḥ}&{tābhyām}&{tābhyaḥ}\\
\textbf{Gen.}&{tasyāḥ}&{tayoḥ}&{tāsām}\\
\textbf{Lok.}&{tasyām}&{tayoḥ}&{tasu}\\%
\end{deklination}

\subsubsection{Neutrum}
\begin{deklination}
\textbf{Nom.}&{tat} (d)&{te}&{tāni}\\
\textbf{Akk.}&{tat} (d)&{te}&{tāni}\\
\textbf{Inst.}&{tena}&{tābhyām}&{taiḥ}\\
\textbf{Dat.}&{tasmai}&{tābhyām}&{tebhyaḥ}\\
\textbf{Abl.}&{tasmāt}&{tābhyām}&{tebhyaḥ}\\
\textbf{Gen.}&{tasya}&{tayoḥ}&{teṣām}\\
\textbf{Lok.}&{tasmin}&{tayoḥ}&{teṣu}\\
\end{deklination}

\end{document}

Answer 1

Hmm I thought it might be

longtabu and floats: wrong table breaks on pages with floats

but it isn't.

Actually I'd use a simpler way to keep headers with the table than the patch suggested, which does the right thing in your case:

\documentclass[open=any, a5paper, fontsize=9pt, DIV12]{scrbook}
\usepackage[utf8x]{inputenc}% only for pdflatex

\usepackage{etoolbox}
\usepackage{array}
\usepackage{longtable}
\usepackage{libertine}
\setcounter{secnumdepth}{-1}

\newcommand{\br}{\hfill\break}


\newenvironment{deklination}[1]
{\setlength{\extrarowheight}{.75ex}%
%\normalLTfalse
\longtable{lp{3cm}p{3cm}p{3cm}}
\noalign{\subsection{#1}}
&\textbf{Sg.}&\textbf{Du.}&\textbf{Pl.}\\
\endhead
}
{\endlongtable}

\usepackage{hyperref}

\begin{document}

\chapter{Lektion IX}

\section{Grammatik}



\begin{deklination}{Pronomen der zweiten Person svad, yuṣmad}
\textbf{Nom.}&{svam}&{yuvām}&{yūvam}\\
\textbf{Akk.}&{svām},\br {svā}&{yuvām},\br {vām}&{yuṣmān},\br {vaḥ}\\
\textbf{Inst.}&{svayā}&{yuvābhyām}&{yuṣmābhiḥ}\\
\textbf{Dat.}&{tuhyam},\br {te} &{yuvābhyām},\br {vām}&{yuṣmabhyam},\br {vaḥ}\\
\textbf{Abl.}&{svat}&{yuvābhyām}&{yuṣmat}\\
\textbf{Gen.}&{tava},\br {te}&{yuvayoḥ},\br {vām}&{yuṣmākam},\br {vaḥ}\\
\textbf{Lok.}&{svayi}&{yuvayoḥ}&{yuṣmāsu}\\
\end{deklination}

\subsection{Pronomen der dritten Person tad – er, sie, es; jener, jene, jenes}

\begin{deklination}{Masculinum}
\textbf{Nom.}&{saḥ}&{tau}&{te}\\
\textbf{Akk.}&{tam}&{tau}&{tān}\\
\textbf{Inst.}&{tena}&{tābhyām}&{taiḥ}\\
\textbf{Dat.}&{tasmai}&{tābhyām}&{tebhyaḥ}\\
\textbf{Abl.}&{tasmāt}&{tābhyām}&{tebhyaḥ}\\
\textbf{Gen.}&{tasya}&{tayoḥ}&{teṣām}\\
\textbf{Lok.}&{tasmin}&{tayoḥ}&{teṣu}\\%
\end{deklination}

\begin{deklination}{Femininum}
\textbf{Nom.}&{sā}&{te}&{tāḥ}\\
\textbf{Akk.}&{tām}&{te}&{tāḥ}\\
\textbf{Inst.}&{tayā}&{tābhyām}&{tabhiḥ}\\
\textbf{Dat.}&{tasyai}&{tābhyām}&{tābhyaḥ}\\
\textbf{Abl.}&{tasyāḥ}&{tābhyām}&{tābhyaḥ}\\
\textbf{Gen.}&{tasyāḥ}&{tayoḥ}&{tāsām}\\
\textbf{Lok.}&{tasyām}&{tayoḥ}&{tasu}
\end{deklination}

\begin{deklination}{Neutrum}
\textbf{Nom.}&{tat} (d)&{te}&{tāni}\\
\textbf{Akk.}&{tat} (d)&{te}&{tāni}\\
\textbf{Inst.}&{tena}&{tābhyām}&{taiḥ}\\
\textbf{Dat.}&{tasmai}&{tābhyām}&{tebhyaḥ}\\
\textbf{Abl.}&{tasmāt}&{tābhyām}&{tebhyaḥ}\\
\textbf{Gen.}&{tasya}&{tayoḥ}&{teṣām}\\
\textbf{Lok.}&{tasmin}&{tayoḥ}&{teṣu}\\
\end{deklination}

\end{document}