Try doing the same thing in your dataset, but don't actually add them as "special tokens", and just let them just be multiple tokens.
Adding new tokens needs a ton of data to train what the token means. Reusing existing tokens, will allow you to easily teach that a sequence of tokens now has a new meaning after fine tuning.
Adding new tokens needs a ton of data to train what the token means. Reusing existing tokens, will allow you to easily teach that a sequence of tokens now has a new meaning after fine tuning.