Bug report – colour-mapped markers on a date x-axis reset axis to 1970

Hi

thank you for the great work on plotly for R. While building a simple time-series chart I noticed that mapping a numeric column to color inside a marker trace shifts the x-axis limits to the Unix epoch (1970-01-01). The same variable works fine when mapped to size. The reproducible examples below illustrate the behaviour. Any guidance or fix would be highly appreciated.

Reprex

library(plotly)
library(data.table)

# dummy data -------------------------------------------------------------
set.seed(1)
dt <- data.table(
  y            = cumsum(rnorm(200)),
  rank         = sample(1:100, 200, TRUE),
  size_metric  = rpois(200, 10),
  datetime     = seq(as.Date("2022-01-01"), by = "day", length.out = 200)
)

# -------- WORKS (no colour mapping) -------------------------------------
plot_ly(dt, type = "scatter", mode = "markers") |>
  add_trace(x = ~datetime, y = ~y,
            name = "points", size = ~size_metric) |>
  add_trace(x = ~datetime, y = ~y,
            name = "line", mode = "lines",
            line = list(color = "black"))
# x-axis shows correct 2022-20xx window

# -------- WORKS (size mapped to same field) -----------------------------
plot_ly(dt, type = "scatter", mode = "markers") |>
  add_trace(x = ~datetime, y = ~y,
            name = "points", size = ~rank) |>
  add_trace(x = ~datetime, y = ~y,
            name = "line", mode = "lines",
            line = list(color = "black"))
# ✓ still correct axis

# -------- FAILS (colour mapping) ----------------------------------------
plot_ly(dt, type = "scatter", mode = "markers") |>
  add_trace(x = ~datetime, y = ~y,
            name = "points", colour = ~rank) |>
  add_trace(x = ~datetime, y = ~y,
            name = "line", mode = "lines",
            line = list(color = "black"))
# ✗ x-axis resets to 1970-01-01

Expected

Axis limits stay within the data’s date range (2022-01-01 … 2022-07-20).

Actual

When colour = ~rank is used, the x-axis jumps to epoch 1970-01-01.

Tested with

packageVersion("plotly")  # 4.10.4
R.version.string          # R 4.3.2 (MacOS Darwing)

Commencez par exécuter le R reprex fourni avec plotly 4.10.4 et comparez le mappage de taille fonctionnel avec le mappage de colour défaillant. Suivez la préparation des marqueurs mappés par colour et des valeurs Date de x ; le travail est terminé lorsque l’axe x reste compris entre 2022-01-01 et 2022-07-20 lors de l’utilisation de colour = ~rank.