Orca exporting Non-ASCII characters

Brief description of the problem
When I save the plot, i realized that the title of the chart is not Côte, but it becomes C?te.
Please advise.

 library(magrittr)
  library(plotly)
#> Loading required package: ggplot2
#> 
#> Attaching package: 'plotly'
#> The following object is masked from 'package:ggplot2':
#> 
#>     last_plot
#> The following object is masked from 'package:stats':
#> 
#>     filter
#> The following object is masked from 'package:graphics':
#> 
#>     layout
plot_ly(economics, x = ~date, y = ~pop) %>% 
  add_annotations(text = "C\u00f4te", x = 0.5, y = 1,
                  yref = "paper", xref = "paper",
                  xanchor = "middle", yanchor = "top",
                  showarrow = FALSE) %>% 
  plotly::orca(file = "\u00f41.png")
#> No trace type specified:
#>   Based on info supplied, a 'scatter' trace seems appropriate.
#>   Read more about this trace type -> https://plot.ly/r/reference/#scatter
#> No scatter mode specifed:
#>   Setting the mode to markers
#>   Read more about this attribute -> https://plot.ly/r/reference/#scatter-mode
#> Warning: `arrange_()` is deprecated as of dplyr 0.7.0.
#> Please use `arrange()` instead.
#> See vignette('programming') for more help
#> This warning is displayed once every 8 hours.
#> Call `lifecycle::last_warnings()` to see where this warning was generated.

提供された R の再現コードを plotly::orca と注釈テキスト "Côte" を使って開始します。保存されたプロットのエクスポート経路を追跡し、結果が非 ASCII 文字を保持していて、"C?te" として出力されていないことを確認します。