Thanks for taking the time to report an issue! Any apologies that I take longer, sometimes way longer, than I should to address them.
There are two important key points for submitting an issue:
- When submitting an issue, please include a complete minimal example.
- When loading maths fonts, please do so by filename only.
- If you are using a proprietary/unusual font, please try a maths font in TeX Live to see if it exhibits the same behaviour; it's obviously much harder for me to test with fonts I don't yet have or can't access.
For example, this is a good minimal example:
\documentclass{article}
\usepackage{unicode-math}
\setmathfont{texgyrepagella-math.otf}
\begin{document}
\[
x^2 + y^2 = z^2
\]
\end{document}
This is an example of a bad example:
\usepackage{unicode-math}
\setmathfont{TeX Gyre Pagella Math}
% later:
\[
x^2 + y^2 = z^2
\]
I'm usually not fussy! Generally I'll just be impressed you've taken the effort.
If you are changing documentation only (i.e., no code changes), you can add [ci skip] to the commit message and the test suite won't be run to check that the changes haven't broken anything.