Not possible to embed cell with subplots in R

I have:

• searched the issue tracker for similar issues
• installed the latest version of Quarto CLI
• formatted my issue following the Bug Reports guide

Bug description

Hello,

I am using a manuscript project. I'm trying to embed from a .qmd file the contents of a chunk that has subplots. According to the guide, it should be possible using the jupyter environment. However I am not able to make it work with the knirt environment.

Thank you in advance for your help!

Steps to reproduce

index.qmd

---
title: embed-issue
authors:
  - name: Juan
---

## Section

{{< embed notebook.qmd#fig-test >}}

notebook.qmd

---
title: "notebook"
---

```{r}
#| label: fig-test
#| fig-cap: this is figure caption
#| fig-subcap: 
#|   - "This is subfig 1"
#|   - "This is subfig 2"
#|   - "This is subfig 3"
#| layout-ncol: 3

hist(x = runif(100))
hist(x = rnorm(100))
plot(x = runif(100), y = rnorm(100))
```

Actual behavior

I obtain the following error code

[1/2] notebook.qmd
[2/2] index.qmd
ERROR: The cell fig-test does not exist in notebook

Expected behavior

All subfigures should be embeded in the index.qmd document, as shown in the guide

Your environment

R version 4.3.0 (2023-04-21 ucrt)
Platform: x86_64-w64-mingw32/x64 (64-bit)
Running under: Windows 10 x64 (build 19045)

Matrix products: default


locale:
[1] LC_COLLATE=German_Germany.utf8  LC_CTYPE=German_Germany.utf8    LC_MONETARY=German_Germany.utf8 LC_NUMERIC=C                   
[5] LC_TIME=German_Germany.utf8    

time zone: Europe/Berlin
tzcode source: internal

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

loaded via a namespace (and not attached):
 [1] digest_0.6.37     R6_2.5.1          later_1.4.1       fastmap_1.2.0     xfun_0.51         knitr_1.50        htmltools_0.5.8.1
 [8] rmarkdown_2.29    ps_1.9.0          cli_3.6.3         processx_3.8.6    compiler_4.3.0    rstudioapi_0.17.1 tools_4.3.0      
[15] quarto_1.4.4      evaluate_1.0.3    yaml_2.3.10       Rcpp_1.0.13-1     rlang_1.1.4       jsonlite_2.0.0   

Quarto check output

Quarto 1.8.25
[>] Checking environment information...
      Quarto cache location: C:\Users\user\AppData\Local\quarto
[>] Checking versions of quarto binary dependencies...
      Pandoc version 3.6.3: OK
      Dart Sass version 1.87.0: OK
      Deno version 2.3.1: OK
      Typst version 0.13.0: OK
[>] Checking versions of quarto dependencies......OK
[>] Checking Quarto installation......OK
      Version: 1.8.25
      Path: C:\Users\user\AppData\Local\Programs\Quarto\bin
      CodePage: 1252

[>] Checking tools....................OK
      TinyTeX: v2025.10
      Chromium: (not installed)

[>] Checking LaTeX....................OK
      Using: TinyTex
      Path: C:\Users\user\AppData\Roaming\TinyTeX\bin\windows\
      Version: 2025

[>] Checking Chrome Headless....................OK
      Using: Chrome found on system
      Path: C:\Program Files (x86)\Microsoft\Edge\Application\msedge.exe
      Source: Windows Registry

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

[>] Checking Python 3 installation....OK
      Version: 3.9.0
      Path: C:/Program Files/Python39/python.exe
      Jupyter: (None)

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

[>] Checking R installation...........OK
      Version: 4.3.0
      Path: C:/PROGRA~1/R/R-43~1.0
      LibPaths:
        - C:/Users/user/AppData/Local/R/win-library/4.3
        - C:/Program Files/R/R-4.3.0/library
      knitr: 1.50
      rmarkdown: 2.29

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