It makes sense that water extinguishes torches, but it is both annoying and unrealistic that a whole stack of torches should get extinguished. Torches carried in your inventory do not get extinguished so it would make sense that only the torch you are holding should get extinguished and not the entire stack since technically you are not holding all of those torches at once. The obvious workaround currently is to only equip single torches and keep stacks of torches in your inventory. I think this change would overall be a good quality-of-life improvement for the game.