Why no significant comparisons?

Question

I have this dataframe:

dput(df)
structure(list(n = c(1, 2, 3, 4, 5, 6, 7, 8, 9, 10), Dose = structure(c(1L, 
2L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L), .Label = c("0", "250"), class = "factor"), 
    Temperature = c(0, 0, 20, 20, 40, 40, 60, 60, 80, 80), BDV = c(50000, 
    40000, 48000, 38000, 46000, 36000, 42000, 32000, 30000, 20000
    )), row.names = c(NA, -10L), class = "data.frame")

and got this plot:

As the option pairwise.display = "significant" is on I know that only significant comparisons should be shown. Hence, when I change it to eg "all" they are shown indeed. But as one can clearly see: There are differences, why are they not treated/shown such?

colnames(df)[3]<- "Temperature"
colnames(df)[4]<- "BDV"
ggbetweenstats(
              data = df
              , x = Temperature
              , y = BDV
              , grouping.var = Dose
              , outlier.tagging  = TRUE
              , map_signif_level = TRUE
              , pairwise.display = "significant"
              #, pairwise.display = "non-significant"              
              #, pairwise.display = "all"             
              , ggtheme = ggplot2::theme_bw()
              #, plotgrid.args    = list(nrow = 1)
              , ggsignif.args    = list(textsize = 4, tip_length = 0.01)
              , results.subtitle = TRUE
              , title = "Distributions and differences between both Doses"
              )