Problem with text in url bookmark and plotOutput

I am trying to use the bookmarked state in a URL for an R Shiny app (hosted on to choose what data to plot. The problem is that renderPlot doesn't plot. Whitespace is left where the plot should be. The javascript console error indicates a problem with string in the url?

"Error: util.addPathParams doesn't implement escaping"

This code replicates the problem. It seems to work OK locally.

#attempt to add bookmarking to rstudio lesson 1 and replicate bug
plotmsg =function(txt){return(plot(1:5,main=txt))} #this is new
ui <-function(request){ fluidPage( #UI wrapped in a function
titlePanel("Old Faithful Geyser Data"),
"Number of bins:",
min = 1,
max = 50,
value = 30),
textInput("w","name",value="a plot title"), #this is new
bookmarkButton() # This is new

  plotOutput("plot"),   # This is new


server <- function(input, output) {
output$plot <- renderPlot(plotmsg(input$w)) #this is new
output$distPlot <- renderPlot({
x <- faithful[, 2]
bins <- seq(min(x), max(x), length.out = input$bins + 1)
hist(x, breaks = bins, col = 'darkgray', border = 'white')

shinyApp(ui = ui, server = server, enableBookmarking = "url") #this has added parameter

This was apparently due to the use of input.w as one of the parameters. encodes the w poorly and then couldn't read it. Seems like a bug. Addressed for my situation by use of different input names.