Broken Shiny table formatting when viewed in flexdashboard

I have a simple table that is rendered correctly as a Shiny app, but becomes broken when embedded into flexdashboard.

Here is what it looks like as a native Shiny app:

But this happens when its embedded into flexdashboard:

This bug is easy to reproduce. The following native Shiny app code is put into bug_test.R:

library(DT)
library(shiny)

ui_test <- fluidPage(
  sidebarLayout(
    sidebarPanel(),
    mainPanel(
      DT::dataTableOutput("table"),
    )
  )
)

server_test <- function(input, output) {

  output$table <- DT::renderDataTable(DT::datatable({
    colA <- c("A", "B", "C")
    colB <- c("X", "Y", "Z")
    colC <- c("1", "2", "3")
    return(data.frame(colA, colB, colC))
  }), options = list(
    dom = "t",
    ordering = FALSE,
    autoWidth = TRUE,
    columnDefs = list(
      list(className = "dt-right", targets = 1),
      list(width = "150px", targets = 0),
      list(width = "200px", targets = 1),
      list(width = "100px", targets = 2)
    )
  ), selection = "none", rownames = FALSE, escape = FALSE)

}

shinyApp(ui = ui_test, server = server_test)

The flexdashboard code (test.Rmd) is:

---
title: "Test"
output: 
  flexdashboard::flex_dashboard:
    orientation: rows
    vertical_layout: scroll
runtime: shiny
---
Tab Name
=======================================================================

```{r}
source("bug_test.R")

shinyApp(ui = ui_test, server = server_test)
```

I am using the latest version of RStudio (2024.04.2, Build 764), and the latest versions of all modules (Shiny 1.8.1.1, DT 0.33, flexdashboard 0.6.2).

Run bug_test.R as a native Shiny app, then render test.Rmd with flexdashboard to compare the table output. Inspect the table formatting in the embedded dashboard and the flexdashboard integration; done means the table widths, alignment, and layout match the native Shiny result.