Missing colors in heatmap if values are the identical

Hello!
when creating a heatmap where values are all the same on a continuous scale, I get the expected colors from ggplot. However, when I put my ggplot into ggplotly, the colors are gone and it's all gray. Only happends, when values are identical. Happens with version 4.9.3 of plotly.

library(ggplot2)
library(dplyr)
library(plotly)

data <- tibble(hour = c(1, 1, 2, 2), day = c(1, 2, 1, 2), evaluation = c(1, 1, 1, 1))
g <- ggplot(data = data, mapping = aes(x = hour, y = day))
g <- g + geom_tile(aes(fill = evaluation), color = "white")
g <- g + scale_fill_gradientn(limits = c(0, 1), colours = c("red", "green"), name = "Availability")

print(g)         # ok, all colors are green as expected
print(ggplotly(g)) # not ok, colors in heatmap are gray, expected to be green

Please let me know if you need more explanation or additional information to track this down.

Thank you and kind regards,
Heiko

Beginne mit dem reproduzierbaren R-Beispiel im Issue und verfolge die ggplotly-Konvertierung für eine kontinuierliche Heatmap, deren Bewertungswerte identisch sind. Vergleiche die Ausgaben von ggplot und ggplotly und überprüfe anschließend, dass die konvertierten Kacheln die erwartete grüne Farbe statt Grau verwenden.