fancychap Glenn: box lines don't connect

Question

In the fancychap preset Glenn, the unnumbered chapters (eg contents, bibliography) don't have any text in the top left corner of the box, and so the corner is visible. The thing is, the lines don't connect at the corner - see image.

Is this a bug or intended, and is there any way to change it to connect and form the complete box?

Here's an example of code that reproduces the bug. I think I've determined that the parskip package is the issue - what in particular could be the conflict, and how could I resolve it?

\documentclass[12pt]{report}
\usepackage[Glenn]{fncychap}
\usepackage{parskip}

\begin{document}

\tableofcontents
\chapter{Introduction}

\end{document}

Edit: resolved, though it was kind of jank. Before each chapter header, I set the \parskip to 0, and immediately after I set it back to 7.25 (the default value in the parskip package). So, each chapter looked something like this:

\setlength{\parskip}{0.0pt plus1.0pt}
\tableofcontents
\setlength{\parskip}{7.25pt plus2.0pt}

\setlength{\parskip}{0.0pt plus1.0pt}
\chapter{Introduction}
\setlength{\parskip}{7.25pt plus2.0pt}
\input{chapters/introduction}

Answer 1

If you really find this style attractive, patch it so it (locally) sets \parskip to zero.

\documentclass[12pt]{report}
\usepackage[Glenn]{fncychap}
\usepackage{parskip}
\usepackage{etoolbox}

\makeatletter
\patchcmd{\@makechapterhead}
  {\parindent}
  {\setlength{\parskip}{0pt}\parindent}
  {}{}
\patchcmd{\@makeschapterhead}
  {\parindent}
  {\setlength{\parskip}{0pt}\parindent}
  {}{}
\makeatother

\begin{document}

\tableofcontents
\chapter{Introduction}

\end{document}

I won't reproduce the output, sorry.

_{I'm also against parskip, but that's a different story.}