I like how the microtype package handles character protrusion when I compile my LaTeX documents with LuaLaTeX. But I have noticed that this doesn't seem to work properly in the bibliography that the biblatex package outputs.

In the minimal working example below, I first show that character protrusion works for both opening and closing quotation marks outside of the bibliography. In the bibliography I have then constructed two references that both have their titles begin on the second line. Opening quotation marks as expected protrude into the left margin, but protrusion does not seem to work for the closing quotation marks. The only difference in the titles is how many i's that I have added to the word "into".

We can see that the title in the first reference is typeset with rather small interword spaces and no protrusion of the closing quotation mark and that when I in the second reference add the third extra "i" there is still no protrusion but the title is instead broken to two lines.

Where does this problem come from? And how should I go about in fixing it? (Or am I just misunderstanding something?)

\documentclass[american]{article}
\usepackage[
  style=authoryear,
  backend=biber,
  dashed=false,
]{biblatex}

\setlength{\bibhang}{0pt}

\usepackage{filecontents}
\begin{filecontents*}{mwe.bib}
  @article{andersson2011,
    title={An article title that ought to have a closing quotation mark that protrudes iiinto the margin},
    author={Anderson, A Lengthy List of First Names to Move the Article Title to the Next Line},
    journaltitle={Review of Utter Nonsense},
    date={2011},
    volume={5},
  }

  @article{andersson2021,
    title={An article title that ought to have a closing quotation mark that protrudes iiiinto the margin},
    date={2021},
    volume={40},
    crossref={andersson2011}
  }
\end{filecontents*}

\addbibresource{mwe.bib}

\usepackage[showframe, text={140mm, 230mm}]{geometry}
\usepackage{babel}
\usepackage[babel]{microtype}
\usepackage[babel]{csquotes}

\begin{document}
  \noindent ``We see that quotation marks protrude into the right margin when outside the bibliography.''

  \nocite{andersson2021,andersson2011}

  \printbibliography
\end{document}

I like how the microtype package handles character protrusion when I compile my LaTeX documents with LuaLaTeX. But I have noticed that this doesn't seem to work properly in the bibliography that the biblatex package produces.

In the minimal working example below, I first show that character protrusion works for both opening and closing quotation marks outside of the bibliography. In the bibliography I have then constructed two references that both have their titles begin on the second line. Opening quotation marks as expected protrude into the left margin, but protrusion does not seem to work for the closing quotation marks. The only difference in the titles is how many i's that I have added to the word "into".

We can see that the title in the first reference is typeset with rather small interword spaces and no protrusion of the closing quotation mark and that when I in the second reference add the third extra "i" there is still no protrusion but the title is instead broken to two lines.

Where does this problem come from? And how should I go about in fixing it? (Or am I just misunderstanding something?)

\documentclass[american]{article}
\usepackage[
  style=authoryear,
  backend=biber,
  dashed=false,
]{biblatex}

\setlength{\bibhang}{0pt}

\usepackage{filecontents}
\begin{filecontents*}{mwe.bib}
  @article{andersson2011,
    title={An article title that ought to have a closing quotation mark that protrudes iiinto the margin},
    author={Anderson, A Lengthy List of First Names to Move the Article Title to the Next Line},
    journaltitle={Review of Utter Nonsense},
    date={2011},
    volume={5},
  }

  @article{andersson2021,
    title={An article title that ought to have a closing quotation mark that protrudes iiiinto the margin},
    date={2021},
    volume={40},
    crossref={andersson2011}
  }
\end{filecontents*}

\addbibresource{mwe.bib}

\usepackage[showframe, text={140mm, 230mm}]{geometry}
\usepackage{babel}
\usepackage[babel]{microtype}
\usepackage[babel]{csquotes}

\begin{document}
  \noindent ``We see that quotation marks protrude into the right margin when outside the bibliography.''

  \nocite{andersson2021,andersson2011}

  \printbibliography
\end{document}