Basically, when i am a small morph if i mine a block too fast when in a smaller morph (less than 1 block tall) it will not actually break, and create ghost blocks instead. So the blocks are still there, but they appear to be gone. this is only an issue with instantly breaking blocks not just breaking a block any way. i tried it in a player-size morph and it was fine. To reproduce, just morph into a bat and break dirt with an eff 4 diamond shovel. This is with all vanilla tools and enchantments that are obtainable in survival without cheats.