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

Start with the reproducible R example in the issue and trace the ggplotly conversion for a continuous heatmap whose evaluation values are identical. Compare the ggplot and ggplotly outputs, then verify that the converted tiles use the expected green color instead of gray.