How to fix an error of fwrite() can write list columns containing items which are atomic vectors?

Question

I merged 5-year monthly dataset and the output is too large that it reached the maximum number of rows in excel. So, I'm thinking of grouping the customer ID so that I will generate unique IDs.

I'm using the following codes to group the customer ID and then export as csv.

final_data <- raw_data %>%
  group_by(Customer_ID) %>%
  pivot_wider(names_from = "snapshot_date_from_filename", values_from = c("Maturity_date", 
                                                                          "Amortization",
                                                                          "Principal",
                                                                          "Balance"))

fwrite(final_data, "Outputs/final_data.csv")

However, I'm having an error as follows:

Row 18635 of list column is type 'NULL' - not yet implemented. fwrite() can write list columns containing items which are atomic vectors of type logical, integer, integer64, double, complex and character.