export to latex not working

[Neal Becker]

My document compiles fine within LyX, but export to LaTeX is not
working (lyx-2.3.3).

Specifically,
export / latex (lualatex)

[3<./system_simulation_block_diagram-2-crop.pdf>](load luc: /home/nbecker/.texl
ive2018/texmf-var/luatex-cache/generic/fonts/otl/lmroman6-bold.luc)
! Missing $ inserted.
<inserted text>
$
l.440 }

?
! Package luatex.def Error: File `"20191022_Fig3(a) and Fig3(b)/jpg/Fig_1(a)_Gr
ant-based transmission for SCMA".jpg' not found: using draft setting.

See the luatex.def package documentation for explanation.
Type  H <return>  for immediate help.
 ...

l.440 }

?

The 1st error, missing $ inserted, suggests to me that some file name
was not quoted correctly?  Yet, when processed within LyX there is no
error message.

Any ideas?