\Bigg et al

[hvoss49]

Without unicode-math verything is fine (cmm is uded) but with loading unicode-math some symbols are missing and some are curious. Running up-to-date TL2017 with lualatex and Linux. It is the same for xelatex

\documentclass{article}
%\usepackage{unicode-math}
\begin{document}
	$\begin{array}{*{17}c}
	() & [\,] & <> & /|\backslash & \lmoustache\,\rmoustache & \arrowvert\vert & 
	\Vert\,\Arrowvert & 
	\uparrow\downarrow & \updownarrow & \Uparrow\Downarrow & \Updownarrow & \langle\rangle 
	& 
	\lbrace\rbrace & \lceil\,\rceil & \lfloor\,\rfloor & \lgroup\rgroup & \bracevert  
	\\[4pt]
	%
	\Bigg(\Bigg) & \Bigg[\,\Bigg] & \Bigg<\Bigg> & \Bigg/\Bigg|\Bigg\backslash & 
	\Bigg\lmoustache\,\Bigg\rmoustache & \Bigg\arrowvert\Bigg\vert & 
	\Bigg\Vert\,\Bigg\Arrowvert & 
	\Bigg\uparrow\Bigg\downarrow & \Bigg\updownarrow & \Bigg\Uparrow\Bigg\Downarrow & 
	\Bigg\Updownarrow & \Bigg\langle\Bigg\rangle & \Bigg\lbrace\Bigg\rbrace & 
	\Bigg\lceil\,\Bigg\rceil & \Bigg\lfloor\,\Bigg\rfloor & \Bigg\lgroup\Bigg\rgroup & 
	\Bigg\bracevert
	\end{array}$
\end{document}

Without unicode-math:

With unicode-math:

[wspr]

See also: latex3/fontspec#308

[wspr]

Cutting this down to the actual problem characters gives me:

\documentclass{article}
%\usepackage{unicode-math}
%\setmathfont{xits-math.otf}
\begin{document}
	$\begin{array}{*{17}c}
  \lmoustache&
  \rmoustache&
  \arrowvert &
  \Arrowvert &
  \bracevert  
	\\[4pt]
	%
	\Bigg\lmoustache&
	\Bigg\rmoustache&
  \Bigg\arrowvert &
	\Bigg\Arrowvert &
	\Bigg\bracevert
	\end{array}$
\end{document}

The moustaches are fixed by loading a different maths font.
The rest I'm not sure about. Perhaps I should un-define them with a sensible error message.