Formatting issue with R chunks with lst-label and lst-cap

Bug description

When using lst-label and lst-cap, the formatting of R chunks is messed up.

When rendering to a pdf, the code is ugly (no syntax coloring, or background shading) but acceptable.
When rendering to a .docx, the code is worse. It is centered, rather than being left-justified, there is no syntax coloring, although the background is shaded.
In the docx file, the code is shown as using the "Source Code" style, but the style settings are over-ridden
The messed up docx occurs whether or not a template docx file is used.

Steps to reproduce

---
title: "Reproducible Quarto Document"
format: docx
engine: knitr
---

This is a minimal self-contained reproducible Quarto document using `format: docx` and `knitr` engine.
It is written in Markdown and contains embedded R code.

This chunk uses the label and caption settings
```{r}
#| warning: false
#| output: false
#| eval: false
#| lst-label: lst-setpaths
#| lst-cap: Set file paths. The paths will need to be edited for your system.  
output_path <- "output/"
figure_path <- "figures/"
```

This one does not
```{r}
output_path <- "output/"
figure_path <- "figures/"
```

Expected behavior

The first chunk should be rendered in the same way as the second,i.e. with syntax colouring, and left-justified text.

Actual behavior

The second chunk renders correctly. The first chunk is not formatted properly. When rendered to a pdf there is no code syntax colouring. When rendered to a .docx, the code is centred and there is no syntax coloring.

Your environment

IDE: Rstudio 2023.12.1 Build 402
OS: Linux Mint Linux Mint 21.3

Quarto check output

Quarto 1.4.549
[✓] 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: 1.4.549
Path: /opt/quarto/bin

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

[✓] Checking LaTeX....................OK
Using: TinyTex
Path: /home/kevin/.TinyTeX/bin/x86_64-linux
Version: 2023

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

[✓] Checking Python 3 installation....OK
Version: 3.10.12
Path: /usr/bin/python3
Jupyter: 5.7.1
Kernels: python3

[✓] Checking Jupyter engine render....OK

R scripting front-end version 4.1.2 (2021-11-01)
[✓] Checking R installation...........(None)

No idea why I get that message about not finding R.
R is running just fine in Rstudio.
Have not had any other issues running Quarto thru Rstudio