Sheep eating grass does not turn grass into dirt when mobGriefing is disabled

I just tested it, and on singleplayer sheep are actually eating grass and grass blocks.

 I just retested in on my multiplayer server, sheeps indeed dont consume the grass. @xParadoxical_

Do you have the gamerule mobGriefing set to false?

Oh yes.. Sorry about the mistake. I usually don't do anything non-vanilla to the server but there were too many creepers everywhere even when its lit due to MC-142134 :/ so I turned off mob-griefing until its fixed but I forgot about it. Sorry about it and please resolve the issue.

Edit: this broke my sheep farm which relies on detecting grass block changes, but I didnt think of that