Hi ! new_fingerprint is computed automatically by taking into account:

the previous dataset fingerprint
a hash of your map function
a hash of the parameters passed to map

So as long as you don’t change your code and you keep the same parameters, the fingerprint will stay the same and the dataset will be reloaded from the disk.
Can you make sure you didn’t change your function or the parameters passed to map ?
Note that preprocessing_num_workers  is part of the parameters passed to map and you must make sure it doesn’t change either.