[NTG-context] units module has bug with markIV?

[Chen Shen]

Hi all,
"\Micro" in the "units" module failed, while "\Nano" and "\Milli" works fine.
"$\mu$" works, so it doesn't look like a font problem.
The following code works with pdftex/MarkII, but fails under Luatex
0.29beta/MarkIV.

\usemodule[units]
\starttext Hello world! $1\Micro\Meter$ $1\Micro\Second$
\stoptext

Any hints? Thanks a lot!

regards,
shenchen