Problem with nested delimiters and subscripts

I ran latexdiff on the following two files:

$ cat test1.tex 
\documentclass{article}
\begin{document}
\begin{equation}
  \left\Vert     [y] \right\Vert_y
\end{equation}
\end{document}

$ cat test2.tex 
\documentclass{article}
\begin{document}
\begin{equation}
  \left\Vert    [y] \right\Vert_x
\end{equation}
\end{document}

I ran the command as follows and got the following output in the difference file:

$ latexdiff --math-markup=whole test1.tex test2.tex > differences.tex
$ cat differences.tex
\documentclass{article}
%DIF LATEXDIFF DIFFERENCE FILE
%DIF DEL test1.tex   Thu Jan 21 10:54:16 2021
%DIF ADD test2.tex   Thu Jan 21 10:54:16 2021
%DIF PREAMBLE EXTENSION ADDED BY LATEXDIFF
%DIF UNDERLINE PREAMBLE %DIF PREAMBLE
\RequirePackage[normalem]{ulem} %DIF PREAMBLE
\RequirePackage{color}\definecolor{RED}{rgb}{1,0,0}\definecolor{BLUE}{rgb}{0,0,1} %DIF PREAMBLE
\providecommand{\DIFadd}[1]{{\protect\color{blue}\uwave{#1}}} %DIF PREAMBLE
\providecommand{\DIFdel}[1]{{\protect\color{red}\sout{#1}}}                      %DIF PREAMBLE
%DIF SAFE PREAMBLE %DIF PREAMBLE
\providecommand{\DIFaddbegin}{} %DIF PREAMBLE
\providecommand{\DIFaddend}{} %DIF PREAMBLE
\providecommand{\DIFdelbegin}{} %DIF PREAMBLE
\providecommand{\DIFdelend}{} %DIF PREAMBLE
\providecommand{\DIFmodbegin}{} %DIF PREAMBLE
\providecommand{\DIFmodend}{} %DIF PREAMBLE
%DIF FLOATSAFE PREAMBLE %DIF PREAMBLE
\providecommand{\DIFaddFL}[1]{\DIFadd{#1}} %DIF PREAMBLE
\providecommand{\DIFdelFL}[1]{\DIFdel{#1}} %DIF PREAMBLE
\providecommand{\DIFaddbeginFL}{} %DIF PREAMBLE
\providecommand{\DIFaddendFL}{} %DIF PREAMBLE
\providecommand{\DIFdelbeginFL}{} %DIF PREAMBLE
\providecommand{\DIFdelendFL}{} %DIF PREAMBLE
%DIF LISTINGS PREAMBLE %DIF PREAMBLE
\RequirePackage{listings} %DIF PREAMBLE
\RequirePackage{color} %DIF PREAMBLE
\lstdefinelanguage{DIFcode}{ %DIF PREAMBLE
%DIF DIFCODE_UNDERLINE %DIF PREAMBLE
  moredelim=[il][\color{red}\sout]{\%DIF\ <\ }, %DIF PREAMBLE
  moredelim=[il][\color{blue}\uwave]{\%DIF\ >\ } %DIF PREAMBLE
} %DIF PREAMBLE
\lstdefinestyle{DIFverbatimstyle}{ %DIF PREAMBLE
    language=DIFcode, %DIF PREAMBLE
    basicstyle=\ttfamily, %DIF PREAMBLE
    columns=fullflexible, %DIF PREAMBLE
    keepspaces=true %DIF PREAMBLE
} %DIF PREAMBLE
\lstnewenvironment{DIFverbatim}{\lstset{style=DIFverbatimstyle}}{} %DIF PREAMBLE
\lstnewenvironment{DIFverbatim*}{\lstset{style=DIFverbatimstyle,showspaces=true}}{} %DIF PREAMBLE
%DIF END PREAMBLE EXTENSION ADDED BY LATEXDIFF

\begin{document}
\DIFdelbegin \begin{displaymath}
  \DIFdel{\left\Vert     }[\DIFdel{y}] \DIFdel{\right\Vert_y
}\end{displaymath}%DIFAUXCMD
\DIFdelend \DIFaddbegin \begin{equation}
  \DIFadd{\left\Vert    }[\DIFadd{y}] \DIFadd{\right\Vert_x
}\end{equation}\DIFaddend 
\end{document}

However, when I ran latex on the difference output, I got an error:

$ pdflatex differences.tex 
This is pdfTeX, Version 3.14159265-2.6-1.40.21 (TeX Live 2020/Arch Linux) (preloaded format=pdflatex)
 restricted \write18 enabled.
entering extended mode
(./differences.tex
LaTeX2e <2020-10-01> patch level 2
L3 programming layer <2020-12-03> xparse <2020-03-03>
(/usr/share/texmf-dist/tex/latex/base/article.cls
Document Class: article 2020/04/10 v1.4m Standard LaTeX document class
(/usr/share/texmf-dist/tex/latex/base/size10.clo))
(/usr/share/texmf-dist/tex/generic/ulem/ulem.sty)
(/usr/share/texmf-dist/tex/latex/graphics/color.sty
(/usr/share/texmf-dist/tex/latex/graphics-cfg/color.cfg)
(/usr/share/texmf-dist/tex/latex/graphics-def/pdftex.def))
(/usr/share/texmf-dist/tex/latex/listings/listings.sty
(/usr/share/texmf-dist/tex/latex/graphics/keyval.sty)
(/usr/share/texmf-dist/tex/latex/listings/lstmisc.sty)
(/usr/share/texmf-dist/tex/latex/listings/listings.cfg))
(/usr/share/texmf-dist/tex/latex/l3backend/l3backend-pdftex.def)
(./differences.aux) (/usr/share/texmf-dist/tex/context/base/mkii/supp-pdf.mkii
[Loading MPS to PDF converter (version 2006.09.02).]
)
! Extra }, or forgotten \right.
\UL@onmath ...rd {\UL@hrest \mathop {\kern \z@ #1}
                                                  \limits \sb {\UL@leadtype ...
l.45   \DIFdel{\left\Vert     }
                               [\DIFdel{y}] \DIFdel{\right\Vert_y
? X
No pages of output.
Transcript written on differences.log.

ftilmann / latexdiff

Problem with nested delimiters and subscripts #220