[2020] Strange experience gains

Working as intended. Many crafting recipes provide experience now; And the exp issued is dependent upon the quantity of resources used. Bundles use 6000 of an item, and give a commensurate reward.

But as you noted, It has diminishing returns and after 5-10 crafts will have diminished to 0 never to give exp again. It can be 'abused' by just crafting, unpacking, and re-crafting it, sure, but, ultimately doing so will just hinder yourself as you'd be artificially boosting your gamestage if you did so to gain a bunch of levels without actually mining up the material and collecting stuff in the interim.