Bug - Scoreboard 'friendlyfire' rule does not work

Lately I have created a minigame of doubles. And I use the following command to remove PvP between teams:

/ scoreboard teams option Game friendlyfire false

This way the players can not be hit or suffer fire damage.
But around 1.11, the rule has stopped working and players continue to take damage. I tested it on 1.8, 1.9, 1.10, and from 1.11 the error happened.
I do not know what might be causing the problem. But it made me very annoyed! Please correct this soon!

Do the following test:

1) Create a world (Can be flat).
2) Create a team using: / scoreboard teams add [Name]
3) Disable PvP: / scoreboard teams option [Name] friendlyfire false
4) Then have all players join the team: / scoreboard teams join [Name] @a
5) Try to kill yourself (: D).

You can easily notice the bug.