Unwanted offset when using biblatex's printbibliography and author bolding via xstring+etoolbox

Question

I'm trying to bold my name in a publication list. After an embarrassing amount of time/experimentation I have something I'm happy with via etoolbox and xstring:

\renewcommand{\mkbibnamegiven}[1]{\ifboolexpr{(test {\IfSubStr{\namepartfamily}{Knowles}} and (test {\IfSubStr{\namepartgiven}{David}})}{\mkbibbold{#1}}{#1}}
\renewcommand{\mkbibnamefamily}[1]{\mkbibnamegiven{#1}}

However, this results in an odd indentation artefact when I do printbibliography twice:

Am I doing something incorrect with the macro or is this an actual bug? Thanks! MWE:

\documentclass[10pt, a4paper]{article}
\usepackage{filecontents}
\usepackage[backend=biber]{biblatex}
\begin{filecontents}{test.bib}
@ARTICLE{Isaev2023-ax,
  title    = "Investigating {RNA} splicing as a source of cellular diversity
              using a binomial mixture model",
  author   = "Isaev, Keren and Knowles, David A",
  journal  = "bioRxiv",
  year     =  2023,
  Keywords = {Working}
}
@ARTICLE{Brown2023-fm,
  title     = "MCFA",
  author    = "Brown†, Brielin C and Knowles†, David A and Lappalainen†, Tuuli",
  journal   = "Cell Genomics",
  year      =  2023,
      bibbase_note = {†Co-corresponding},
  Keywords = {Genetics}
}
\end{filecontents}
\addbibresource{test.bib}
\usepackage{xstring}
\usepackage{etoolbox}
\renewcommand{\mkbibnamegiven}[1]{\ifboolexpr{(test {\IfSubStr{\namepartfamily}{Knowles}} and (test {\IfSubStr{\namepartgiven}{David}})}{\mkbibbold{#1}}{#1}}
\renewcommand{\mkbibnamefamily}[1]{\mkbibnamegiven{#1}}
\begin{document}
\nocite{*}
\printbibliography[title=Journal articles, type=article, keyword=Genetics]
\noindent % doesn't help
\setlength{\parindent}{0pt}
\printbibliography[title=Working, type=article, keyword=Working]
\end{document}

Answer 1

The round brackets aren't properly matched inside the \ifboolexpr. Unfortunately, etoolbox does not warn about it, it just messes up the surrounding typesetting.

The following MWE (without any round brackets - they were not required here) works as intended

\documentclass[10pt, a4paper]{article}
\usepackage[backend=biber]{biblatex}
\usepackage{xstring}
\renewcommand{\mkbibnamegiven}[1]{%
  \ifboolexpr{    test {\IfSubStr{\namepartfamily}{Knowles}}
              and test {\IfSubStr{\namepartgiven}{David}}}
    {\mkbibbold{#1}}
    {#1}}
\renewcommand{\mkbibnamefamily}[1]{\mkbibnamegiven{#1}}
\begin{filecontents}{\jobname.bib}
@ARTICLE{Isaev2023-ax,
  title    = "Investigating {RNA} splicing as a source of cellular diversity
              using a binomial mixture model",
  author   = "Isaev, Keren and Knowles, David A",
  journal  = "bioRxiv",
  year     =  2023,
  Keywords = {Working}
}
@ARTICLE{Brown2023-fm,
  title     = "MCFA",
  author    = "Brown†, Brielin C and Knowles†, David A and Lappalainen†, Tuuli",
  journal   = "Cell Genomics",
  year      =  2023,
  bibbase_note = {†Co-corresponding},
  Keywords = {Genetics}
}
\end{filecontents}
\addbibresource{\jobname.bib}
\begin{document}
\nocite{*}
\printbibliography[title=Journal articles, type=article, keyword=Genetics]
\printbibliography[title=Working, type=article, keyword=Working]
\end{document}