Comments below valueboxes do not display as expected

When adding a comment below a valuebox, the text is absorbed into the valuebox itself. When the comment is above the chart it is wrapped in <blockquote> but it behaves differently below charts, especially for valueboxes. Perhaps I am missing something?

Working from a basic template:

---
title: "Untitled"
output: 
  flexdashboard::flex_dashboard:
    orientation: columns
    vertical_layout: fill
---

```{r setup, include=FALSE}
library(flexdashboard)
```

Column {data-width=650}
-----------------------------------------------------------------------

>Comment ABOVE

### valuebox1Infectious

```{r}
flexdashboard::valueBox(1000000, caption = 'Cool caption', icon = 'fas fa-calendar-alt')
```

> Comment BELOW

Column {data-width=350}
-----------------------------------------------------------------------

### Chart B

```{r}
plot(mtcars$cyl)
```

This produces:

Start with the basic flexdashboard template in the issue and compare how the above-chart and below-chart comments render around the valueBox. Reproduce the behavior, then trace the valuebox and comment rendering paths. Done means a comment below a valuebox is displayed outside the valuebox with the expected blockquote behavior.