Bug Report: tbl_stack() header alignment when exported to pdf via as_kable_extra() with \n in modify_header()

[shannonpileggi]

In individual tbl_summary() outputs utilizing modify_header() with \n line breaks, column headers render to pdf as expected (centered).

However, when combining tables via tbl_stack(), outputs utilizing modify_header() with \n line breaks, column headers render to pdf as trt 1 left justified and trt 2 centered.

Here is the output:

Here is the source .Rmd:

---
output: pdf_document
---

```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = FALSE)

library(tidyverse)
library(gtsummary)

t1 <- trial |> 
  select(trt, age) |> 
  tbl_summary(
    by = trt
  )

Table 1

t1 |> 
  modify_header(
    all_stat_cols() ~ "**{level}**\nN = {n}"
  ) |> 
  as_kable_extra()

t2 <- trial |> 
  select(trt, grade) |> 
  tbl_summary(
    by = trt
  )

Table 2

t2 |> 
  modify_header(
    all_stat_cols() ~ "**{level}**\nN = {n}"
  ) |> 
  as_kable_extra()

Stack Table 1 & Table 2, then modify header

tbl_stack(list(t1, t2)) |> 
  modify_header(
    all_stat_cols() ~ "**{level}**\nN = {n}"
  ) |> 
  as_kable_extra()

Modify header in Table 1, then stack

t1_modify <- t1 |> 
  modify_header(
    all_stat_cols() ~ "**{level}**\nN = {n}"
  )

tbl_stack(
  list(t1_modify, t2),
  quiet = TRUE
  ) |> 
  as_kable_extra()