Spurious comma when using biblatex-chem with beamer

[josephwright]

From https://github.com/josephwright/biblatex-chem/issues/12

\documentclass{beamer}
\usepackage[ngerman]{babel}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{lmodern}
\usepackage{csquotes}
\usepackage[backend=biber, style=chem-angew]{biblatex}
\addbibresource{biblatex-examples.bib}

\begin{document}
\begin{frame}
\cite{doody}
\printbibliography
\end{frame}

shows an additional comma:

[josephwright]

As noted in the other question, I have a feeling this relates to https://github.com/josephwright/beamer/issues/331 and probably https://github.com/josephwright/beamer/issues/347.

[samcarter]

The spurious comma is added by beamer in https://github.com/josephwright/beamer/blob/master/base/beamerbaselocalstructure.sty#L493 (the \bbx@tempa adds it)

(no solution, just to locate the problem)