I created a new report as my old report was marked as invalid.

(The old report was MCPE-137701)

(This affects all touchscreen devices)

Whenever you charge a bow on a TS-Device, you will not be able to change the inventory slot. Because of this, you will have to fire an arrow and have no option to change to another slot unlike consoles and keyboard and mouse devices where you can press a key to change slot.