[luatex] font problem

[Herbert Voss]

With xelatex both values for 1ex are the same, but
with lualatex I get  (10.67352pt) versus (3.43344pt)
The reason why the sans serif \LaTeX is not correct.
This happens only for LinBiolinum_R.otf and I do not
know why.

\documentclass{article}
\usepackage{fontspec}
\setmainfont{Linux Libertine O}
\setsansfont{Linux Biolinum O}
\newdimen\EX
\begin{document}
\Huge
\LaTeX (\EX=1ex \the\EX)

\sffamily
\LaTeX (\EX=1ex \the\EX)

\end{document}

Herbert