I am using lualatex to typeset documents with Adobe Garamond Pro, using the mathdesign package with the "adobe-garamond" option for the math fonts. However, this nets me a warning upon loading fontspec,
LaTeX Font Warning: Font shape `EU2/lmr/sb/n' undefined
(Font) using `EU2/lmr/m/n' instead on input line 356.
This warning remains whether I load a font with fontspec or not. It has no relevance whatsoever to the output: even if the final document has no Latin Modern at all, it is displayed! It is specific to the "adobe-garamond" option: if I were to use mathdesign with another font option, it would disappear.
Here is a mwe:
\documentclass{minimal}
\usepackage[adobe-garamond]{mathdesign}
\usepackage[no-math]{fontspec}
%\setmainfont{whatever!}
\begin{document}
This is a test.
\end{document}
What is the source of this behavior? Is there a way to cleanly remove the warning, or at least silence it?