Scrap bone knife increases the skill at all levels

[rocky grotto]

Stone Dagger, Neolithic Axe and Stone Hammer behave the same

[gilded fractal]

Thanks for reporting. If you are able to confirm the version numbers you are running, that would be helpful.

Someone else has (informally) reported this, so I suspect there is a bug that has crept in somewhere. We'll make sure it gets looked at.