Luascript in a mergeallfiles macro no longer working in lualatex

On Windows 11 I am using a package based on=C2=A0Alan Xiang's answer at:

https://tex.stackexchange.com/questions/722886/how-to-write-out-multiple-te=
xt-files-from-multiple-instances-of-latex-environmen

but it seems to have stopped working.

The relevant code is:


% call this function to merge all subfiles to one file
\cs_new:Npn=C2=A0 \MergeAllFiles #1
{
=C2=A0 =C2=A0 \prop_get:NnNF \g_doc_counter_lut_prop {#1} \l_doc_counter_tl
=C2=A0 =C2=A0 {
=C2=A0 =C2=A0 =C2=A0 =C2=A0 \GenericError{}{invalid~filename~("#1")}{}{}
=C2=A0 =C2=A0 }
=C2=A0 =C2=A0 \iow_open:Nn \g_tmpa_iow {#1}
=C2=A0 =C2=A0 \int_step_inline:nn {\l_doc_counter_tl}
=C2=A0 =C2=A0 {
=C2=A0 =C2=A0 =C2=A0 =C2=A0 \doc_copy_file_content:nN {#1-##1.vrb} \g_tmpa_=
iow
=C2=A0 =C2=A0 }
=C2=A0 =C2=A0 \iow_close:N \g_tmpa_iow
}

Did something change in Windows? Lualatex? (I did update MikTex trying to t=
roubleshoot this)

William


--=C2=A0
Sphinx of black quartz, judge my vow.
https://designinto3d.com/