Getting and Illegal Character Errror when creating a formula using openxlsx2

Question

I am trying to automate the creation of a workbook and I have written a for loop that looks like it is creating the formulas correctly (see below), but when I open the excel file I get this message:

Followed by this message:

Here is the code:

library(openxlsx2)
wb = wb_workbook()
wb$add_worksheet('IS_Rec')

isRecFormula2 =  data.frame(matrix(ncol = 0, nrow = 2847))
for (i in 7:38){
  
  column = toupper(paste0(letters[floor((i+2)/26)],letters[(i+2)%%26],sep=''))
  isRecFormula2[,i-6]=paste0("IF(",column,"$1=\"elim\",G",as.numeric(row.names(isRecFormula2))+5L,"-H",as.numeric(row.names(isRecFormula2))+ 5L,",IFERROR(VLOOKUP($B",as.numeric(row.names(isRecFormula2))+5L,",INDIRECT(",column,"$3&\"!$a$1:$qq$4000\"),MATCH(",column,"$4,INDIRECT(",column,"$3&\"!$a$1:$qq$1\"),0),FALSE),0)+IFERROR(VLOOKUP($B",as.numeric(row.names(isRecFormula2))+5L,",INDIRECT(",column,"$3&\"!$a$1:$qq$4000\"),MATCH(",column,"$5,INDIRECT(",column,"$3&\"!$a$1:$qq$1\"),0),FALSE),0))",sep='')
  class(isRecFormula2[,i-6]) = c(class(isRecFormula2[,i-6]),"formula")
  
}

wb$add_data(sheet='IS_Rec',dims = "I6", x= isRecFormula2, col_names = F, na.strings ='')
wb_save(wb, file = "test.xlsx", overwrite = T, )

I hard coded some references in the above to simplify, but this does recreate the error for me.

Anyone have any thoughts on how to troubleshoot?

Thank you!