ggplotly() creates a wrong legend in some cases

Given

library(ggplot2)
library(plotly)
d1 <- data.frame(X=1:10, Y= (1:10)^2, b=paste0("B",1:10),d="d1")
d1$Y2 <- d1$Y+2
gg2 <- ggplot(data=d1, aes(label=b)) +
  geom_point(aes(x=X, y=Y, col="blue")) +
  geom_line(aes(x=X, y=Y2, col="orange")) +
    scale_color_manual(values=c("blue","orange"),
                       labels=c("Left","Center"),
                       name="") 

print(gg2) results in:

But
ggplotly(gg2)

results in:

I know a more conventional code such as:

d1 <- data.frame(X=1:10, Y= (1:10)^2, b=paste0("B",1:10),position="left")
d2 <- data.frame(X=1:10, Y= (1:10)^2 + 2, b=paste0("B",1:10),position="center")
d <- rbind(d1,d2)
gg2 <- ggplot(data=d, aes(label=b)) +
  geom_point(data=d[d$position=="left",],aes(x=X, y=Y,col=position)) +
  geom_line(data=d[d$position=="center",],aes(x=X, y=Y,col=position)) +
  scale_color_manual(values=c("blue","orange","red"),
                     labels=c("Left","Center"),
                     name="") 
gg2
ggplotly(gg2)

results in similar legends, but I wonder if the 1st example is not uncovering a bug in ggplotly()

Start by running the reproducible R example from the issue and compare the ggplot2 and ggplotly legends. Investigate the ggplotly conversion of manual colour scales and verify that the converted legend matches the declared Left and Center labels without extra entries.