\babelfont fails with some fonts as of recent update

[d125q]

(I don’t have a lot of time to troubleshoot, but leaving this here just in case. I began observing this behavior after a recent update.)

\babelfont{sf}{URW Classico} fails with

Illegal parameter number in definition of \l__exp_internal_tl.
<to be read again> 
1
l.76 \babelfont{sf}{URW Classico}

yet \babelfont{rm}{TeX Gyre Pagella} and \babelfont{tt}{IBM Plex Mono} work without any problems. Using the original fontspec commands (e.g., \setsansfont) also works just fine.

I am compiling with

% lualatex --version
This is LuaHBTeX, Version 1.18.1 (TeX Live 2025/dev)
Development id: 7616

Execute  'luahbtex --credits'  for credits and version details.

There is NO warranty. Redistribution of this software is covered by
the terms of the GNU General Public License, version 2 or (at your option)
any later version. For more information about these matters, see the file
named COPYING and the LuaTeX source.

LuaTeX is Copyright 2022 Taco Hoekwater and the LuaTeX Team.

and

\ProvidesPackage{babel}[2024/04/20 v24.4 The Babel package]

[u-fischer]

That is a fontspec issue and will hopefully be resolved in 1-2 days. See https://github.com/latex3/fontspec/issues/513

[d125q]

Thanks @u-fischer! I thought something was off with babel as I could use the fontspec commands. Closing this issue.