Vertical misalignment of the references

Question

In my references a strange vertical misalignment appeard in the writing of each name, for example:

And I really don't know why this happen...

MWE (.cls file)

\NeedsTeXFormat{LaTeX2e}
\ProvidesClass{solutionclass}[2023/03/03 My Custom LaTeX Class for exercise solutions]

\LoadClass[a4paper, twoside, 11pt]{book}

\RequirePackage[portuguese, english]{babel} 
\RequirePackage[utf8]{inputenc} 
\RequirePackage[T1]{fontenc} 
\RequirePackage[backend    = biber, 
            style      = ext-authoryear-comp,
            sorting    = nyvt, 
            backref    = false,
            articlein  = false,
            uniquename = true,
            doi        = true, 
            dashed     = false]{biblatex}
\addbibresource{bib.bib}
\DeclareFieldFormat[article,periodical]{volume}{\mkbibbold{#1}}

\AtEndDocument{%
    \clearpage
    \pagestyle{fancy}
    \markboth{\textsc{References}}{\textsc{References}}
    \printbibliography[heading=bibintoc, title=References]
} 

MWE (.bib file)

@book{Choquet-BruhatGR,
    title = {General Relativity and the Einstein Equations},
    author = {Choquet-Bruhat, Yvonne},
    date = {2009},
    volume = {I},
    publisher = {Oxford University Press},
    location = {Oxford}
}

@book{Choquet-BruhatGR2,
    title = {Introduction to general relativity, black holes, and cosmology},
    author = {Choquet-Bruhat, Yvonne},
    date = {2015},
    volume = {I},
    publisher = {Oxford University Press},
    location = {Oxford}
}

Answer 1

Assuming standard settings, your bibliography is typeset as justified text - just like normal text in the rest of your document. This means that TeX tries to make all lines meet up evenly on the right margin. This is as opposed to left aligned text, where text does not meet up evenly on the right margin and has a more "ragged" look.

Justification is mainly achieved by slightly enlarging or compressing the width of spaces in a line. That's exactly the effect you show in the screenshot. Because the text that is typeset in these lines is different and has different natural width, TeX has to compress/enlarge the spaces to compensate for the different width and make the line ends meet up nicely.

\documentclass[a4paper, 11pt, british]{article}
\usepackage[T1]{fontenc}
\usepackage{babel}
\usepackage{csquotes}

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

\begin{filecontents}{\jobname.bib}
@book{Choquet-BruhatGR,
  title     = {General Relativity and the {Einstein} Equations},
  author    = {Choquet-Bruhat, Yvonne},
  date      = {2009},
  volume    = {I},
  publisher = {Oxford University Press},
  location  = {Oxford},
}
@book{Choquet-BruhatGR2,
  title     = {Introduction to General Relativity, Black Holes, and Cosmology},
  author    = {Choquet-Bruhat, Yvonne},
  date      = {2015},
  volume    = {I},
  publisher = {Oxford University Press},
  location  = {Oxford},
}
\end{filecontents}
\addbibresource{\jobname.bib}
\addbibresource{biblatex-examples.bib}

\begin{document}
Lorem \autocite{sigfridsson,Choquet-BruhatGR,Choquet-BruhatGR2}

\printbibliography
\end{document}

You can get the same spaces if you give up justification. But of course then you no longer have even right edges. This may actually not be too bad in a bibliography, where most entries are not that long anyway.

\documentclass[a4paper, 11pt, british]{article}
\usepackage[T1]{fontenc}
\usepackage{babel}
\usepackage{csquotes}
\usepackage{ragged2e}
\usepackage[backend=biber, style=authoryear, dashed=false]{biblatex}

\begin{filecontents}{\jobname.bib}
@book{Choquet-BruhatGR,
  title     = {General Relativity and the {Einstein} Equations},
  author    = {Choquet-Bruhat, Yvonne},
  date      = {2009},
  volume    = {I},
  publisher = {Oxford University Press},
  location  = {Oxford},
}
@book{Choquet-BruhatGR2,
  title     = {Introduction to General Relativity, Black Holes, and Cosmology},
  author    = {Choquet-Bruhat, Yvonne},
  date      = {2015},
  volume    = {I},
  publisher = {Oxford University Press},
  location  = {Oxford},
}
\end{filecontents}
\addbibresource{\jobname.bib}
\addbibresource{biblatex-examples.bib}

\begin{document}
Lorem \autocite{sigfridsson,Choquet-BruhatGR,Choquet-BruhatGR2}

\begingroup
\RaggedRight
\printbibliography
\endgroup
\end{document}