Index Entries Disappear with the Use of pgfpagesuselayout{2 on 1} [2022, June: Question Still Relevant]

Question

Consider the index generated by the following code:

\documentclass{article}

\usepackage{imakeidx}
\makeindex
\usepackage{idxlayout}
\usepackage{pgfpages}
%\pgfpagesuselayout{2 on 1}

\begin{document}
\LARGE
Part of a sentence. \index{First index entry.}

Part of a sentence. \index{Second index entry.}

Part of a sentence. \index{Third index entry.}

\idxlayout{columns=1}
\printindex

\vspace{1cm}\centering\LARGE The indices disappear when I use pdfpagesuselayout$\{$2 on 1$\}$. 
\end{document} 

However, when I run the same code with \pgfpagesuselayout{2 on 1}, the index on the second page contains no entries:

QUESTION: Does anyone know why the index entries disappear with the use of \pgfpagesuselayout{2 on 1} and how it may be corrected?

Thank you.