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]])

首先运行 issue 的 R 复现，使用 plot_ly(type="box") 以及连续的 add_boxplot(x=y[[...]] ) 调用，将两个 trace 与三个 trace 进行比较。跟踪 add_boxplot 如何处理 NA_real_ 输入和 x 轴类别分配。完成的标准是，与两个 slot 的示例相比，添加空 slot 不会改变显示的数据或 x 轴标签。