I walk up to a smelting machine.. this is what happens.

I open character menu (C) click the skills tab and look at "current" under the stat the machine should be increasing.. nothing is happening. So I click create item and choose something that would normally use that skill.

When the item creation screen comes up, the current skill is adjusted for the bonus for the machine.. then I look at the character menu under skills tab (which I still have open) and lo and behold.. it's been adjusted now to match the skill it was before and now has the bonus added for the machine.

Now I can switch to whatever I need to as far as other formulas requiring that skill and the bonus sticks to whatever I select or properly updates the character screen to reflect the correct "current" skill including the machine bonus.. however you want to look at it.

When I try the same thing with stoneworking (adult statue) there is no bonus on either the character skill -current tab under stoneworking nor in the item creation window. Granted, I don't have anything else that I know of as a dragon to try to build to see if it goes beyond stoneworking bonuses, but it's definitely broken for the adult statue for both a hatchling trying trying to get through their ROP and even an adult dragon tried it and had the same results.