plot_ly boxplot showing wrong x-axis

Suppose I have a list with three slots, but data for slots 2 and 3 are not yet available. When plotting a boxplot with just the first two slots, everything works as expected:

library(plotly)
y <- list("Group 1" = c(105,74,20), 
          "Group 2" = NA_real_, 
          "Group 3" = NA_real_)

boxplot <- plot_ly(type="box")

boxplot %>% 
  add_boxplot(x=y[[1]]) %>%
  add_boxplot(x=y[[2]])

But when trying to plot data for all three slots (where slots 2 and 3 don't have data), then the x-axis label is messed up and the data seems to be messed up as well. (I expected the boxplot to look exactly the same as the one above.)

boxplot %>% 
add_boxplot(x=y[[1]]) %>%
add_boxplot(x=y[[2]]) %>%
add_boxplot(x=y[[3]])

まず、plot_ly(type="box") と add_boxplot(x=y[[...]] ) の連続した呼び出しを使って issue の R 再現を実行し、2 つのトレースと 3 つのトレースを比較します。add_boxplot が NA_real_ 入力と x 軸のカテゴリ割り当てをどのように処理するかを追跡します。2 スロットの例と比べて、空のスロットを追加しても表示データや x 軸ラベルが変わらなければ完了です。