babel/polyglossia shorthands not working

[pcdi]

I cannot get babel/polyglossia's shorthands to work in biblatex.

I found this approach https://tex.stackexchange.com/a/548047/ claiming it was a problem with autolang=hyphen. Testing all the different options for autolang did, however, not yield any different results with regard to the problem in my case.

MWE typeset with LuaHBTeX, Version 1.22.0 (TeX Live 2025) and Biber 2.21:

\documentclass{article}

\usepackage{polyglossia}

\setdefaultlanguage[
  variant=usmax
]{english}
\inheritbabelshorthands{german}{english}

\setotherlanguage[babelshorthands=true]{german}

\usepackage[autolang=langname]{biblatex}

\begin{filecontents}{\jobname.bib}
  @Collection{KammlerFoucaultHandbuch,
    date             = {2020},
    editor           = {Kammler, Clemens and Parr, Rolf and Schneider, Ulrich Johannes},
    location         = {Stuttgart},
    publisher        = {J.\,B.~Metz\-ler},
    title            = {\textgerman{Foucault"=Handbuch}},
  }

  @Collection{KammlerFoucaultHandbuchLangId,
    date             = {2020},
    editor           = {Kammler, Clemens and Parr, Rolf and Schneider, Ulrich Johannes},
    location         = {Stuttgart},
    publisher        = {J.\,B.~Metz\-ler},
    title            = {Foucault"=Handbuch},
    langid           = {german},
  }
\end{filecontents}

\addbibresource{\jobname.bib}

\begin{document}
\parbox{2em}{\textgerman{Foucault"=Handbuch} \\ Foucault"=Handbuch}
\nocite{*}
\printbibliography
\end{document}