set.seed() doesn't create identical outputs across different .rmd files?

Question

I have two .Rmd files that reference the same dataset, but when I use set.seed(), I get different outputs:

library(tidymodels)

# load data and setup
data("ames")

ames_mod <-
  ames %>%
  select(First_Flr_SF, Sale_Price) %>%
  mutate(across(everything(), log10))

# split into train/test data
set.seed(918)
ames_split <- initial_split(ames_mod)
ames_train <- training(ames_split)
ames_test <- testing(ames_split)

When I run this in one file, I get the following:

When I run in another, I get this:

I'm not sure why this is happening - I assume something in the environment is different but I have no idea what could be causing this. I've copied + pasted the code directly & still get different results - in the interim I'm just saving the output from one .Rmd & loading it into the other. If anyone has any ideas or a direction to start looking, I'd be greatly appreciative!