Using the beamer document class, I would like to split a long list of references over multiple slides. As recommended by M. Tibbits in another stack exchange question, one should use allowframebreaks. This, however, resulted in two unnecessary page breaks after the final slide before the appendix. See the working example below. Note that if [allowframebreaks] is removed, then the two phantom pages disappear.
Question: Why do the phantom pages appear, and how do I get rid of them?
\documentclass{beamer}
\usepackage[unnumberedbib,bibnewpage]{apacite}
\begin{document}
\begin{frame}
\frametitle{Title}
\begin{itemize}
\item This is a citation \citeA{citation1}
\item This is another citation \citeA{citation2}
\end{itemize}
\end{frame}
\appendix
\begin{frame}[allowframebreaks]
\bibliographystyle{apacite}
\begin{flushleft}
\bibliography{stack_exchange_library}
\end{flushleft}
\end{frame}
\end{document}
My library, stack_exchange_library.bib, is:
@article{citation1,
title={Title of citation 1},
author={Smith, John},
journal={Blacksmithing},
year={2010},
}
@article{citation2,
title={Title of citation 1},
author={Farmer, Joe},
journal={Farming},
year={2011},
}