Web version ignores .sty file located above current directory

[prowlett]

I make a sty file containing some commands, for example like this:

\newcommand{\mycommand}{chirun folks}

I put this in a folder with a tex file like this:

\documentclass{article}
\usepackage{mystyle}
\begin{document}
Hello \mycommand.
\end{document}

The output (web left, PDF right) looks like this, as expected.

I move the sty file to the directory above (say because I want to use the same sty with multiple files in different subdirectories) and change the LaTeX to this:

\documentclass{article}
\usepackage{../mystyle}
\begin{document}
Hello \mycommand.
\end{document}

Then no error is given but the output is like this.

That is, pdflatex is happy but in the web version the sty has been quietly ignored.

Out of interest (not my use case) I moved the sty file to a subdirectory at sty/mystyle.sty and this worked fine. So the problem seems to be with moving up the directory structure.

\documentclass{article}
\usepackage{sty/mystyle}
\begin{document}
Hello \mycommand.
\end{document}