在下面的shiny应用程序中，我首先用read_csv导入到rstudio后显示数据，然后用read.csv（）将数据上传到shiny应用程序。第一种情况是正确的，在第二个空单元格中给了我NAs。为什么会发生这种情况

## app.R ##
library(shiny)
library(shinydashboard)
library(readr)
#eventex <- read_csv("eventlog_new_format3011.csv")
eventex<-structure(list(case_id = "0003397585", action = "0003397585-B52-R", 
                        resource = "B52-R", activity = NA_character_, registration_type = "Stopp", 
                        timestamp = structure(NA_real_, tzone = "", class = c("POSIXct", 
                                                                              "POSIXt")), `Prod antall` = 3743, product_type_text = "Skyr Luftig tropisk 130gx8", 
                        Ordrenummer = "0003397585", lifecycle = NA, `Sum of TotalQty` = 3743, 
                        Produkt = "K101322", PurchaseItem = NA_character_, Innsatsfaktor = "K101171", 
                        Artikkeltype = "FP", `Alt. Work Center` = NA_character_), row.names = c(NA, 
                                                                                                -1L), class = c("tbl_df", "tbl", "data.frame"))
ui <- dashboardPage(
  dashboardHeader(

  ),
  dashboardSidebar(
    fileInput("file1", "",
              accept = c(
                "text/csv",
                "text/comma-separated-values,text/plain",
                ".csv")),
    radioButtons("separator","Separator: ",choices = c(";",","), selected=",",inline=TRUE)
  ),
  dashboardBody(
               verbatimTextOutput("pr"),
               verbatimTextOutput("pr2")),
  
)

server <- function(input, output,session) {
  
    View(eventex[74,4])
    
    dataset<-reactive({
      inFile <- input$file1
      
      if (is.null(inFile))
        return(NULL)
      
      p1<-read.csv(inFile$datapath, header = T,sep = ",")
      

    })
output$pr<-renderPrint(
  eventex[74,4]
)
output$pr2<-renderPrint(
  dataset()[74,4]
)
}

shinyApp(ui, server)