I can reproduce a LuaHBTeX/luaotfload crash with a very small Tibetan example. Environment: - LuaHBTeX 1.15.0 - TeXLive 2022/Debian (also with TeXLive 2024/Debian) - luaotfload 3.23 (also with 3.29) - fontspec with `Renderer=HarfBuzz` - font: `Tendar_Dutsa.ttf`, available on https://github.com/OpenPecha/tibetan-fonts/tree/main/Unicode%20Font%20Families%20%26%20Typefaces/Tendar%20Font%20Family Minimal repro, with `Tendar_Dutsa.ttf` (you'll have to rename the font with a `_` instead of the space) next to the `.tex` file: ```tex \documentclass{article} \usepackage{fontspec} \setmainfont{Tendar_Dutsa.ttf}[ Path=./, Renderer=HarfBuzz, RawFeature={script=tibt} ] \begin{document} ང། \end{document} ``` ``` This is LuaHBTeX, Version 1.15.0 (TeX Live 2022/Debian) restricted system commands enabled. (./testbug.tex LaTeX2e <2022-11-01> patch level 1 L3 programming layer <2023-01-16> (/usr/share/texlive/texmf-dist/tex/latex/base/article.cls Document Class: article 2022/07/02 v1.4n Standard LaTeX document class (/usr/share/texlive/texmf-dist/tex/latex/base/size10.clo)) (/usr/share/texlive/texmf-dist/tex/latex/fontspec/fontspec.sty (/usr/share/texlive/texmf-dist/tex/latex/l3packages/xparse/xparse.sty (/usr/share/texlive/texmf-dist/tex/latex/l3kernel/expl3.sty (/usr/share/texlive/texmf-dist/tex/latex/l3backend/l3backend-luatex.def))) (/usr/share/texlive/texmf-dist/tex/latex/fontspec/fontspec-luatex.sty (/usr/share/texlive/texmf-dist/tex/latex/base/fontenc.sty) (/usr/share/texlive/texmf-dist/tex/latex/fontspec/fontspec.cfg))) No file testbug.aux. (/usr/share/texlive/texmf-dist/tex/latex/base/ts1cmr.fd) warning (node filter): error: ...exmf-dist/tex/luatex/luaotfload/luaotfload-ha rf-plug.lua:815: attempt to index a nil value (local 'character') . <argument> ...ype:D \tex_hskip:D \c_zero_dim \fi: \tex_par:D \hook_use:n {para/after}\@... l.10 \end{document} ```