There seems to be a bug when your life skill tool skill is invalid which happened only recently(August). So when this happened it seems some skill on the tool(for example here: minigame difficulty reduction) is null and you instead face the higher difficulty in minigame(such as in excavating) where the safe zone are smaller and speed is faster.
Unequipping the tool and reequipment seems to works sometimes but not consistently. Anyone saw bug like this?