ggplotly shows wrong tooltip with geom_sf() and discrete fill scale

This is a copy of my question on Stack Overflow, because I suspect it's not intended behaviour.

I'm trying to create maps that'll show tooltips on hover with plotly. In the maps below, I've tried to make it show the name and the area of each place.

The first map, which has a continuous fill scale, shows the tooltip I'm asking for. But the second map, doesn't. The only difference is that the fill scale is discrete.

What's going on, and how can I fix it?

library(pacman)
p_load(sf, ggplot2, dplyr, plotly)

nc <- st_read(system.file("shape/nc.shp", package = "sf"), quiet = TRUE) %>% 
    mutate(x = factor(c(rep("a", 50), rep("b", 50))),
           TEXT = paste(NAME, AREA))

# It works when I've got a continuous fill scale
p1 <- nc %>% 
    ggplot() +
    geom_sf(aes(fill = AREA, text = TEXT))
#> Warning: Ignoring unknown aesthetics: text

ggplotly(p1, tooltip = "text") %>% 
    style(hoverlabel = list(bgcolor = "white"), hoveron = "text")

Why does this map say "a"?

# But it doesn't work with a discrete fill scale
p2 <- nc %>% 
    ggplot() +
    geom_sf(aes(fill = x, text = TEXT))
#> Warning: Ignoring unknown aesthetics: text

ggplotly(p2, tooltip = "text") %>% 
    style(hoverlabel = list(bgcolor = "white"), hoveron = "text")

EDIT: turns out even the continuous map sometimes shows weird tooltips. Some areas show the right one, as above, others show "Trace XX":

From Stack Overflow answer: someone suggested removing hoveron = "text", which partially works. It shows the right tooltips, but only on the outlines of the shapes, so you don't know which shape it's referring to. Some shapes you can't get the tooltip at all, such as this one:

まず、提供された R の例を ggplotly()、geom_sf()、連続および離散の塗りつぶしスケール、tooltip = "text" を使って実行します。p1 と p2 で生成されたツールチップを比較し、hoveron = "text" を使うケースも含めます。各ポリゴンが "a" や "Trace XX" ではなく、常にその NAME と AREA を表示すれば完了です。