ggplotly: Incorrect display of x-axis with geom_bar in the case of one axis label

[Safstat]

Hello,
I installed the new version of plotly (3.4.1) and I have found this problem:
The display of x-axis is incorrect with geom_bar when we have only one axis label
-- whereas it works fine when I just run the ggplot().
Here's my code:

df <- data.frame(Class = c("A","B","S","H","G","F","P","W","Y","X"),
                   Y_value = c(3,0,0,20,50,0,0,4,0,0),
                   Var2 = c("56","56","56","56","56","56","56","56","56","56"))
plot<-ggplot(df,aes(factor(Var2, levels=unique(as.character(Var2))),fill=Class, Y_value)) +
  geom_bar(stat="identity", colour="black", size=0.35,show.legend = TRUE)+
  theme_grey()+
  xlab("")+ ylab("")
ggplotly(plot)

whereas when I just run the ggplot() I obtain x-axis well displayed

plot