The bug
If the gamerule commandBlockOutput is set to false command feedback of commands executed for a player is not shown anymore. It used to be shown in 1.11.2.
How to reproduce
Open 1.11.2
Set
commandBlockOutputtofalse/gamerule commandBlockOutput falseUse the following command
/execute @p ~ ~ ~ setblock ~ ~ ~ stone→ It says "Block placed"
Repeat steps 3 and 4 in the latest version
→ There is no command feedback
I want to add that having this on false, a command with execute in it, in a command block will also not show the output box