gplot2 not colouring bars when addpvalue() is used

Question

I am having a problem with a ggplot code. I am trying to generate a coloured barplot somewhat similar to those generated in PRISM. All is working well, but as soon as I try to introduce colour with the fill argument in aes, running the add_pvalue() function returns the following error:

Error: ! Problem while computing aesthetics. i Error occurred in the 3rd layer. Caused by error in FUN(): ! object 'Group' not found Run rlang::last_trace() to see where the error occurred.

The data is organised in two columns: Group (grouping variable) and Luminescence (continuous variable).

The code itself looks like this:

# 1 - Make data frame
df <- as.data.frame(Data3)

# 2 - Calculate standard deviations for each group

# 2.1 - Function to calculate mean and SD
data_summary <- function(data, varname, groupnames) {
  require(plyr)
  summary_func <- function(x, col) {
    c(
      mean = mean(x[[col]], na.rm = TRUE),
      sd = sd(x[[col]], na.rm = TRUE)
    )
  }
  data_sum <- ddply(data, groupnames,
    .fun = summary_func,
    varname
  )
  data_sum <- rename(data_sum, c("mean" = varname))
  return(data_sum)
}

# 2.2 - Summarise data to get means and SDs

df3 <- data_summary(Data3,
  varname = "Luminescence",
  groupnames = c("Group")
)

# 3 - Create and call bar plot. Note sig levels: ns, * = p<0.05, ** = p<0.01, *** = p<0.001

df_p_val <- rstatix::t_test(Data3, Luminescence ~ Group, ref.group = "OSCC alone") %>%
  rstatix::add_xy_position()

p <- ggplot(df3, aes(x = Group, y = Luminescence, fill = Group)) +
  geom_bar(stat = "identity", position = position_dodge(), width = 0.5) +
  geom_errorbar(aes(ymin = Luminescence - sd, ymax = Luminescence + sd),
    width = 0.1, position = position_dodge(.9)
  ) +
  theme_prism() +
  theme(axis.text.x = element_text(size = 8), axis.text.y = element_text(size = 8), axis.title = element_text(size = 10)) +
  scale_y_continuous(expand = c(0, 0), limits = function(x) {
    c(0, ceiling(max(x) * 1.1))
  }) +
  scale_x_discrete(labels = function(x) str_wrap(x, width = 10)) +
  add_pvalue(df_p_val, label = "p.adj.signif")

p

Note that if I run the code without fill=Group, the barplot is generated but in black and white, while if I run the code as is without add_pvalue, it does generate coloured bars.

Thanks for any help everyone!

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