is not UTF-8 encoded - Portuguese language .qmd not rendering to html correctly after updating RStudio

Hi all,
I updated RStudio today (Windows 10, RStudio 2024.04.0, Quarto 1.4.554).
My .qmd file that was rendering to html before the update now returns symbols for accented Portuguese text.
When rendering I now get the message: [WARNING] is not UTF-8 encoded: falling back to latin1.
Example of what the html file now looks like:
Example that was produced before the update:

Below is a simplified version of the .qmd file content, session info and result of terminal check quarto.

Any suggestions as to how I can solve this. I have uninstalled and reinstalled RStudio, restarted my laptop etc.
Many thanks,

title: "Animais domésticos: análises descritivas"
author: "Darren Norris"
lang: pt-BR
toc: true
toc-location: left
link-citations: true
pdf: default
editor: source

#| label: set-sys
#| include: false
Sys.setlocale("LC_TIME", "Portuguese")


Aqui utilizamos o caso dos animais domésticos do Campus Marco Zero.


#| label: before-after-inds
#| echo: false
#| message: false

# month without accent in name
data_inicio <- as.Date("2024-04-15")
# month with accent in name
data_final <- as.Date("2024-03-15")
label_inicio <- format(data_inicio, '%B %Y')
label_final <- format(data_final, '%B %Y')

Entre r label_inicio e r label_final foram registrados
45 animais domésticos no campus Marco Zero.

Session info

R version 4.4.0 (2024-04-24 ucrt)
Platform: x86_64-w64-mingw32/x64
Running under: Windows 10 x64 (build 19045)

Matrix products: default

[1] LC_COLLATE=English_United States.utf8 LC_CTYPE=C
[3] LC_MONETARY=English_United States.utf8 LC_NUMERIC=C
[5] LC_TIME=English_United States.utf8

time zone: America/Cayenne
tzcode source: internal

attached base packages:
[1] stats graphics grDevices utils datasets methods base

loaded via a namespace (and not attached):
[1] compiler_4.4.0 fastmap_1.1.1 cli_3.6.2 htmltools_0.5.8.1
[5] tools_4.4.0 rstudioapi_0.16.0 yaml_2.3.8 rmarkdown_2.26
[9] knitr_1.46 xfun_0.43 digest_0.6.35 rlang_1.1.3
[13] evaluate_0.23

check quarto

$ quarto check
Quarto 1.4.554
[>] Checking versions of quarto binary dependencies...
Pandoc version 3.1.11: OK
Dart Sass version 1.69.5: OK
Deno version 1.37.2: OK
[>] Checking versions of quarto dependencies......OK
[>] Checking Quarto installation......OK
Version: 1.4.554
Path: C:\Users\user\AppData\Local\Programs\Quarto\bin
CodePage: 1252

[>] Checking tools....................OK
TinyTeX: (external install)
Chromium: (not installed)

[>] Checking LaTeX....................OK
Using: TinyTex
Path: C:\Users\user\AppData\Roaming\TinyTeX\bin\windows
Version: 2024

[>] Checking basic markdown render....OK

[>] Checking Python 3 installation....OK
Version: 3.7.0
Path: C:/Users/user/AppData/Local/Programs/Python/Python37/python.exe
Jupyter: (None)

  Jupyter is not available in this Python installation.
  Install with py -m pip install jupyter

[>] Checking R installation...........OK
Version: 4.4.0
Path: C:/PROGRA~1/R/R-44~1.0
- C:/Users/user/AppData/Local/R/win-library/4.4
- C:/Program Files/R/R-4.4.0/library
knitr: 1.46
rmarkdown: 2.26

[>] Checking Knitr engine render......OK