Profession bonus

Does anyone know if you unlearn a profession, do you lose the bonus that you get from the profession? For example jewelry crafting, if you unlearn it will you lose the bonus gems? Or enchanting, where you get the bonus enchant for the rings. If you unlearn enchanting do you lose the enchant form the rings?

Yes, you should lose the bonus. Gems and enchants will remain there visually but they should not be active. It works correctly on wotlk but I don't know about the other expansions.