Highchart Grid hc_grid() works fine in RStudio IDE but not in shinyapps.io

I have this problem bellow when I try to deploy my shinyapp.
The image shows when I finisih the first attempt to deploy the app.

The problem is that each chart from the grid is not displayed properly (see the image bellow)

But, when I refresh or change mannualyy the width/height of the browser the chart correts itself.

Bellow is the code:


df <-tibble(months = month.abb, value = ts(cumsum(rnorm(100)))[1:12]  )

ui <- fluidPage(

server <- function(input, output, session) {
  output$chart_grid<- renderUI({
    charts <- lapply(1:9, function(x) {
    highchart() %>% 
        hc_add_series(type = 'spline',data = df, hcaes(x = months,y = value))%>%
        hc_xAxis(categories = df$months)
      hw_grid(charts, rowheight = 300,add_htmlgrid_css = TRUE)%>%


shinyApp(ui, server)

How do I fix this problem to have on the first attempt the highchart grid displayed properly?