R Shiny - dataset load in a first chunk doesn'

I have a strange error in a shiny app I built with the library learnr. An error "Object not found" about an object I just loaded and just visualized (meaning the object exists no ?)

Although I don't have a reproducible example, some of you will maybe understand what is creating the error :

I have a first chunk {r load} that loads a dataset. There is no error here, I can even visualize the dataset (screenshot below)
Then I have a second chunk, where I would like to manipulate the dataset. But it tells me dataset doesn't exist ! How it could be possible, I just visualized it one chunk before ?! ...

I don't understand how a dataset could be exists in a chunk, and not in another. Does it mean the dataset isn't loaded in the global environment ? Is it a problem with the learnr library ?

Maybe someone will have an idea, or something I could test. Thank you in advance.

EDIT: The problem is about the environment/workspace. In the first chunk, even if I load the dataset, it is not store in the environment. I tested the function ls() in a second chunk, and it tells me there is no object in the workspace. The loaded dataset is not here, I don't know why ...

In my opinion, shiny doesn't store any data. You have to pass it manually from one chunk to other as follow (only adding the code snippet from server):

server <- function(input, output, session) {
  output$heat <- renderPlotly({
    Name<-c("John","Bob","Jack")
    Number<-c(3,3,5)
    Count<-c(2,2,1)
    NN<-data.frame(Name,Number,Count)
    render_value(NN) # You need function otherwise data.frame NN is not visible
    # You can consider this as chunk 1
  })

  render_value=function(NN){
   # Here your loaded data is available
     head(NN)
   # You can consider this as chunk 2 
    })  
  }           
}

shinyApp(ui, server)

You can find full code here: Subset a dataframe based on plotly click event

Create global.R file as suggested here and follow this URL: R Shiny - create global data frame at start of app