BibLaTeX: autolang=hyphen causing translation of key terms

Question

I am writing a multilingual document and want bibliography entries properly hyphenated for their language. I do not want to translate terms in the bibliography like "in", "p.", and "edited by". As I read the BibLaTeX documentation, autolang=hyphen should do this, and it seems to me that it worked in the past, but now it also causes the translation of terms used in the bibliography, like "pp." to "S." for a German entry, which is what I would expect from autolang=other. Here's a MWE:

\documentclass[a4paper]{article}
\usepackage{polyglossia}
\setdefaultlanguage[variant=american]{english}
\setotherlanguage{german}
\usepackage{csquotes}
\usepackage[style=verbose-ibid,autolang=hyphen,backend=biber]{biblatex}
\addbibresource{biblatex-examples.bib}
\begin{document}
Here I cite Sigfridsson\autocite{sigfridsson} and Spiegelberg\autocite{spiegelberg}.
\printbibliography
\end{document}

The example bibliography entries use langid to specify the language ("american" and "german" respectively). I get this (with similar results in the footnotes):

Update: since the problem was identified as a bug, I add some version numbers in case anyone reads this in the future: BibLaTeX 3.7, Polyglossia 1.42.4.

Answer 1

Update polyglossia support in biblatex should be functionally equivalent to babel support in biblatex 3.14 (or above) and polyglossia 1.46 (or above).

At the moment polyglossia support in biblatex is still quite shaky. Language version detection (american vs. british) does not work at all right now.

The environment used with autolang=hyphen is hyphenrules, which needs an exception when processed by biblatex's polyglossia interface. This is addressed in issue #564 on the github bug tracker.

Things should work as expected again in the upcoming release. If you don't need polyglossia features, you can always switch to babel. Currently babel support is more mature and stable.