It is possible to craft items if you have max items (125/125) in your backpack. The crafted items will fall to the ground without any error message. I noticed it with cartography. I did not check any other crafting skills. Steps to reproduce: If you have 124/125 items in your backpack and click the 'Make Max' button in the crafting menu it will not stop at 125/125 items. The crafted items will fall to the ground. If you have 125/125 items in your backpack and try this you will get an error message that your backpack is full. I assume that it should also stop with an error message if you reach the 125/125 items.