Basically on the 1.12 minecraft pocket edition, it doesnt show the shield on the player when you switch to inventory,nor does it show it when you are just walking around in general. The stacking bug is basically when you craft something in your inventory, not a crafting table, and you double tap the item you want to put back it wont let it one select stacks. Only after a little bit of double tapping and making new stacks will it work. Hope this helps, great work!