R Flexdashboard: Navigation captions don't show up in hidden storyboard

Question

I am building a Flexdashboard. On the start page there should be links leading to several hidden storyboard (i.e. so that the storyboards do not show up in the navigation bar at the top).

However, it appears that using {.hidden} on a storyboard page interferes with the navigation captions: only the first caption of three is visible: Screenshot

Using the arrows one can still access all three graphs but without the captions.

Does anybody know how to make hidden storyboard-pages work?

I am using R 4.2.0; Flexdashboard 0.5.2; RStudio 2022.02.1 Reproducible example:

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

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

Start page
===========================================================
[Link](#storyboard)

Storyboard{.storyboard .hidden}
===========================================================

### Chart A
```{r}
boxplot(mtcars$mpg)
```

### Chart B
```{r}
boxplot(mtcars$cyl)
```

### Chart C
```{r}
boxplot(mtcars$hp)
```