Black symbols in the \listoffigures \listoftables

Question

I want to add a \listoffigures and \listoftables at the end of the document. Whole document was created with latexmk under Linux. So far so good, no errors by creating the document. By inserting \listoffigures and \listoftables in the document, I get some strange behaviour with black symbols at the page, see

I know this behaviour from the document with black symbols at the end of a sentence, when the hyphenation doesn't work correct and the word "is to long" for the line. Then I have to correct it and all is fine.

The expected hyphentation in picture 2 like is Lig-ges-me-yer. I put here the code from the relevant chapter for the table. The relevant part is the caption. By using the command \citeauthor, the hyphentation seems not work...

\begin{table}[!htbp]
\renewcommand{\arraystretch}{1.5}
\begin{tabular}{ | p{0.36\textwidth} | p{0.18\textwidth} | } 
\hline 
Eingabebereich: & 1 $ \leq \ $ Wert $\leq$ 99 \\
Gültige Äquivalenzklasse: & 1 $ \leq \ $ Wert $\leq$ 99 \\ 
Ungültige Äquivalenzklasse: & Wert $ \leq $ 1 \\ 
Ungültige Äquivalenzklasse: & Wert $ \geq $ 99 \\ \hline
\end{tabular} 
\caption{Beispiel zur Aufteilung in entsprechende Äquivalenzklassen (vgl. \protect\citeauthor{Liggesmeyer2009}, 2009).}
\label{tab:Äquivalenzklassen}
\end{table}

Thank you for all hints!

Question: How can i change this behaviour here? Thanks for hints!

Complete example:

\begin{document}
\begin{table}[!htbp]
    \renewcommand{\arraystretch}{1.5}
    \begin{tabular}{ | p{0.36\textwidth} | p{0.18\textwidth} | } 
    \hline 
    Eingabebereich: & 1 $ \leq \ $ Wert $\leq$ 99 \
    Gültige Äquivalenzklasse: & 1 $ \leq \ $ Wert $\leq$ 99 \ 
    Ungültige Äquivalenzklasse: & Wert $ \leq $ 1 \ 
    Ungültige Äquivalenzklasse: & Wert $ \geq $ 99 \ \hline
    \end{tabular} 
    \caption{Beispiel zur Aufteilung in entsprechende Äquivalenzklassen (vgl. \protect\citeauthor{Liggesmeyer2009}, 2009).}
    \label{tab:Äquivalenzklassen}
    \end{table}
\clearpage
\listoffigures
\clearpage
\clearpage
\listoftables
\par
\clearpage
\lstlistoflistings
\clearpage
\bibliographystyle{apacite}
\bibliography{misc/literatur}
\end{document}