# Bib2Gls doesn't compile CJK characters correctly

I hope it's okay to start a new question, as there are similar ones, but not this exact one (afaik).

It all started with this guide, which is exactly what I need for my paper :) Glossaries with CJK characters and which I tried to restructure to use it with LuaLaTeX instead of the original pdfLaTeX: Define special sorting for Lualatex glossaries in Japanese?

Now, I am facing a way more basic issue, which I would like to tackle first, before trying to build that "dual glossary beast" (in a positive way :D), since it didn't work for me and I was trying to get to the problem's roots.

I tried using the most simple MWE of the first link using glossaries-extra (compiling as pdflatex).

\documentclass{article}

\usepackage{CJKutf8}
\usepackage[record,style=indexgroup]{glossaries-extra}

\newrobustcmd{\cjkname}[1]{\begin{CJK}{UTF8}{min}#1\end{CJK}}
\glsnoexpandfields

\newcommand{\bibglslettergrouptitle}[4]{\unexpanded{\cjkname{#1}}}

src=testcjk,% bib file
sort={ja-JP}% locale
]

\begin{document}

\begin{CJK}{UTF8}{min}ルート\end{CJK}

\gls{squareroot}

\printunsrtglossaries
\end{document}


with the bib file

@dualentry{squareroot,
name={\cjkname{ルート}},
description={square root}
}


The problem is now, when I run Bib2Gls, it creates a glstex file with wrong characters. Instead of

ルート

it compiles (this is just a section of the whole glstex file, which includes the wrong character)

\bibglssetlettergrouptitle{{繝}{繝}{350879744}{}}
\bibglssetlettergrouptitle{{S}{s}{6422528}{}}

\bibglssetlastgrouptitle{\bibglslettergroup}{{繝}{繝}{350879744}{}}
\providecommand*{\bibglsflattenedhomograph}[2]{#1}
\providecommand{\bibglsnewdualentry}[4]{%
\longnewglossaryentry*{#1}{name={#3},#2}{#4}%
}

\bibglsnewdualentry{dual.squareroot}%
{descriptionplural={\cjkname{繝ｫ繝ｼ繝�}s},
plural={square roots},
sort={square|root|},
group={\bibglslettergroup{S}{s}{6422528}{}}}%
{square root}%
{\cjkname{繝ｫ繝ｼ繝�}}

\bibglsnewdualentry{squareroot}%
{descriptionplural={square roots},
plural={\cjkname{繝ｫ繝ｼ繝�}s},
location={\glsnoidxdisplayloc{}{page}{glsnumberformat}{1}},
sort={繝|ｫ|繝|ｼ|繝|},
group={\bibglslettergroup{繝}{繝}{350879744}{}}}%
{\cjkname{繝ｫ繝ｼ繝�}}%
{square root}


Thus, if I then recompile pdflatex, it gives me

I realise, the question relates to the questions asked in the links above, however, this one is more precise in the problem I am facing and the other ones could not really solve my problem.

Thank you and sorry!