When unlearning a profession, the confirmation window reads “Your specialization knowledge will remain should you return to this profession”. DO NOT BELIEVE THIS.
Sadly, I did. On my old main from 2008-2022. I had all the herbalism progress you could have, save some of the DF knowledge. I saw the text on the unlearn window and thought “maybe i should try JC, my new main also herbs. I can always relearn and get my knowledge back”. WRONG!
I lost all my herbalism knowledge. Not a happy camper now.