Discrepancy between usepackage and setmathfont

[ImAWerewolfDuck]

Hello, I found a weird behaviour when using the package on ctan compared to loading the font through setmathfont.
When using the font through the package, the scaling does not apply to mathrm (and therefore to other packages like siunitx) and microtype complains about "Unknown slot number of character" which cant be fixed using DeclareMicrotypeAlias or DeclareCharacterInheritance.
When using setmathfont, microtype still complains but can be patched by aforementioned commands. Additionally, the font scaling is correct in all environments.
MWE using usepackage compiled with LuaLaTeX:

\documentclass[a4paper, 12pt]{report}\usepackage{fontspec}
\usepackage[bold-style=ISO]{unicode-math} 
\usepackage{microtype}
\setmainfont[Scale=0.5]{Lato}
\usepackage[Scale=0.5]{lete-sans-math}
\usepackage[detect-all]{siunitx}
\begin{document}\noindent
	\begin{align}
		&\text{This is in normal text}\\
		&This\ is\ in\ math\\
		&\mathrm{This\ is\ in\ mathrm}\\
		&This\ is\ in\ siunitx\ inside\ math: \SI{1337}{\milli\mole}
	\end{align}	
\end{document}

MWE using setmathfont compiled with LuaLaTeX:

\documentclass[a4paper, 12pt]{report}
\usepackage{fontspec}
\usepackage[bold-style=ISO]{unicode-math}
\usepackage{microtype}
\setmainfont[Scale=0.5]{Lato}
\setmathfont[Scale=0.5]{LeteSansMath}
\usepackage[detect-all]{siunitx}
\begin{document}\noindent
	\begin{align}
		&\text{This is in normal text}\\
		&This\ is\ in\ math\\
		&\mathrm{This\ is\ in\ mathrm}\\
		&This\ is\ in\ siunitx\ inside\ math: \SI{1337}{\milli\mole}
	\end{align}	
\end{document}

[dflipo]

This is a bug introduced in version 0.45, scaling options have been forgotten :-(

For a quick fix, comment out lines 51-53 in lete-sans-math.sty.