Operator is able to use commands, even when cheats are turned off

If one player is in Operator Mode, even when cheats are disabled, /give commands do work, if the space between /give and @s are removed, for example:

/give@s stone 1

 

How to reproduce:

1. Generate a new world, Cheats turned off and gamemode Survival
2. /give@s stone 1   (You can use which Block and Quantity you like)
3. feel free to test the commands listed below and add accordingly

 

Other commands tested and work: 

1.  /tp
2.  /kill
3.  /op@player
4.  /fill~~~
5.  /setblock
6.  /xp
7.  /execute 
8. most of the @s commands tried so far
9. many commands (e.g. fill~~~) if you leave out the space