Cannot have more than one shape after subplot()

I guess this is related to #1333

Here is the issue: it doesn't seem possible to have more than one shape after subplot() is called. Applying the shapes to the individual plots work, though.

reprex that works:

library(plotly)

p1 <- plot_ly(mtcars, x = ~mpg, y = ~hp) %>% 
  layout(
    shapes = list(
      list(
        type = "line", 
        line = list(color = "#5681c4", dash = "dot"),
        x0 = 20, 
        x1 = 20,
        y0 = 0,
        y1 = 1,
        yref = "paper"
      ),
      list(
        type = "line", 
        line = list(color = "#5681c4", dash = "solid"),
        x0 = 30, 
        x1 = 30,
        y0 = 0,
        y1 = 1,
        yref = "paper"
      )
    )
  ) %>%
  config(editable = TRUE)

p2 <- plot_ly(mtcars, x = ~mpg, y = ~drat) %>% 
  layout(
    shapes = list(
      list(
        type = "line", 
        line = list(color = "#5681c4", dash = "dot"),
        x0 = 20, 
        x1 = 20,
        y0 = 0,
        y1 = 1,
        yref = "paper"
      ),
      list(
        type = "line", 
        line = list(color = "#5681c4", dash = "solid"),
        x0 = 30, 
        x1 = 30,
        y0 = 0,
        y1 = 1,
        yref = "paper"
      )
    )
  ) %>%
  config(editable = TRUE)

subplot(p1, p2, nrows = 2)

reprex that does not work:

library(plotly)

p1 <- plot_ly(mtcars, x = ~mpg, y = ~hp)

p2 <- plot_ly(mtcars, x = ~mpg, y = ~drat)

subplot(p1, p2, nrows = 2) %>% 
  layout(
    shapes = list(
      list(
        type = "line", 
        line = list(color = "#5681c4", dash = "dot"),
        x0 = 20, 
        x1 = 20,
        y0 = 0,
        y1 = 1,
        yref = "paper"
      ),
      list(
        type = "line", 
        line = list(color = "#5681c4", dash = "solid"),
        x0 = 30, 
        x1 = 30,
        y0 = 0,
        y1 = 1,
        yref = "paper"
      )
    )
  ) %>%
  config(editable = TRUE)

reprex with only one shape - it works:

library(plotly)

p1 <- plot_ly(mtcars, x = ~mpg, y = ~hp)

p2 <- plot_ly(mtcars, x = ~mpg, y = ~drat)

subplot(p1, p2, nrows = 2) %>% 
  layout(
    shapes = list(
      type = "line", 
      line = list(color = "#5681c4", dash = "dot"),
      x0 = 20, 
      x1 = 20,
      y0 = 0,
      y1 = 1,
      yref = "paper"
    )
  ) %>%
  config(editable = TRUE)

Any thoughts?

Start by running the working and failing reprexes in the issue, comparing shapes supplied to each plot with shapes added after subplot(). Trace how subplot() combines the plots and how the later layout(shapes = ...) call is handled. Done means both shapes render on the subplot and remain editable with config(editable = TRUE).