Phone : Asus Zenphone 2 ZE551ML, Android 5.0 (with the Asus Launcher unmodified and not root)

Hello Mojang, I found an other bug during my map making : when I used the commands /fill like /fill ~-20 ~ ~-20 ~+20 ~ ~+20 air 0 replace dirt 0 the command work... but one block under where I am (so the floor under the feet).
I tried with /tp ~ ~ ~, move and re-tp me at these coordinates but I wasn't teleported one block under so I think that this bug don't touch all commands. I tried to do with the /testforblock * and the game searched one block under the block I said and the same issue with the */setblock command.

Maybe this can touch also /playsound, /setworldspawn or others but I it not possible for me to check all of them (like for the /playsound because I can't see sound) and it seems to only execute one block under on the Z axis so it's not so bad because we can add one more one the Z axis part of these commands (like /setblock ~ ~ +1 ~ dirt to place the block at the high of the feet like it will work with just "~ ~ ~".
Note : For the last command I can't write ~ and +1 next or ~ is invisible