Issue when undoing deletion in nested list

Steps to reproduce

Load this document:
```
\documentclass[12pt,a4paper]{article}
```

%! \usepackage[utf8]{inputenc} \usepackage{geometry} \usepackage{lmodern} \usepackage[T1]{fontenc} \usepackage{graphicx} \graphicspath{{./}} \usepackage{csquotes}

\begin{document}

\title{Title} \maketitle

\section{Section}

Paragraph

\begin{enumerate} \item Item 1

\begin{enumerate} \item Subitem 1 \item Subitem 2 \end{enumerate}

\item Item 2 \end{enumerate}

\end{document}

- Select the two subitems (selection from "Subitem 1" up to and including "Subitem 2")
- Delete the selection (Delete backward/forward)
- Undo the deletion (Cmd+U)
- At this point, the document source is not restored to the original state:

\documentclass[12pt,a4paper]{article}