Problems with working with the siunitx package

[wrfwerrr]

Description

When I use the siunitx package to output units, Latin letters in math mode are not displayed.

Add info or delete as appropriate:

\mu and \beta are not displayed when I compile with XeLaTex.

Minimal example demonstrating the issue

\documentclass{book}

\usepackage{siunitx}
\usepackage{unicode-math}
\setmathfont{texgyrepagella-math.otf}

\begin{document}
\SIrange{1}{2}{\mu\beta  aaa}
\end{document}