>From Pablo, see https://github.com/wspr/unicode-math/issues/208
If you load a font twice using different rendering modes, it gets
embedded twice:
\input luaotfload.sty
\font\1={name:LM Roman 10 Regular:mode=node}\relax
\font\2={name:LM Roman 10 Regular:mode=base}\relax
\1 A
\2 A
\bye
Regards,
Philipp Stephani