I am using XeLaTeX and unicode-math with the Libertinus Math font. Some symbols are missing therefore I'm using the range command. Then I get an unwanted crossed-square symbol beside big curly braces. Here is a MWE.
\documentclass{article}
\usepackage{unicode-math}
\setmathfont{Libertinus Math}
\setmathfont[range={\rightrightarrows,\twoheadrightarrow}]{xits-math.otf}
% The seemingly useleess command below is needed for a different known bug
\setmathfont[range={\int}]{Libertinus Math}
\begin{document}
\[
\Bigl\{\Bigr\}
\]
\end{document}
Known bug in the comment above: Unicode-math changes font outside of range
Does anybody know if this is a known bug? Is there a solution?
EDIT: I just found a workaround here. Is there a "cleaner" solution?

unicode-mathversion 0.8j, released 2018-01-07. – egreg Jan 10 '18 at 12:03