Shiny value boxes with same textOutput disappear

Question

It seems I can't have the same textOutput() in 2 different value boxes. I didn't mean to do this but it took me 2 hours of troubleshooting to realize what the problem is. Is there a reason this fails?

1 value box is fine:

2 value boxes with the same textOutput() is not.

If you uncomment the first section, you'll see that the reactive values disappear. I'm curious why this happens, if this is a bug, and if so, what package do I report it to?

shinyApp(
  ui = fluidPage(
    # value_box(
    #   title = "Title",
    #   value = textOutput("x"),
    #   showcase = bs_icon("rocket-takeoff-fill")
    # ),
    value_box(
      title = "Title", 
      value = textOutput("x"), 
      showcase = bs_icon("rocket-takeoff-fill")
    )
  ),
  server =  function(input, output, session) {
    output$x <- renderText({ nrow(cars) })
    output$y <- renderText({ nrow(cars) })
  }
) |>
  runApp(launch.browser = rstudioapi::viewer)

Answer 1

From Jan:

This is not a bug, you just can't use the same id twice because this generates invalid html. You could have a look at modules in order to avoid conflicting ids