renderText scrollbar even with css command won't work inside column

For me to currently add a scrollbar to renderText (using renderUI), I have to do the following gymnastics:

---
title: "my title"
runtime: shiny
output:
   flexdashboard::flex_dashboard:
   orientation: rows
   theme: cerulean
   source_code: embed
---

```{r global, include=FALSE}
library(tidyverse)
# more code here
```

# Sidebar {.sidebar data-width=150}

```{r}
# stuff on sidebar
```
# Page {.hidden}

## Text

```{r}
scroll_css <- "<style> #section-text {overflow-y: scroll;} </style>"
renderUI({
  to_print <- str_c(scroll_css, some_line, "<br>", some_other_line) 
  htmltools::HTML(to_print)
})
```

However, if instead of ## Text above I did

## Column

### Text

```{r}
scroll_css <- "<style> #section-text {overflow-y: scroll;} </style>"
renderUI({
  to_print <- str_c(scroll_css, some_line, "<br>", some_other_line) 
  htmltools::HTML(to_print)
})
```

scroll bar (as determined by the css styling line) will no longer work

I would be grateful if (a) renderText({ ... }) would actually produce a scrollbar automatically when the text was too long, or somehow the above problem would be fixed.

Overall, using flexdashboard is appealing but the package seems to be pretty erratic, controls don't alway render, etc. So hopefully there will be enough time to push for bug fixing here.

Start by reproducing the issue's flexdashboard example using renderUI, the nested Column/Text layout, and the #section-text CSS rule. Compare the top-level Text case with the nested case and determine whether the scrollbar behavior can be corrected; done means the CSS-based scrollbar works inside the nested column without the extra workaround.