Seemed to have accidentally typed a client command into chat? Never used clients so don't know how they work but here's a screen of chat. We suspected him yesterday when we used invisibility potions to raid his base and he seemed to see us right through it. We talked to Littlethreat and Theepicpun. Hope this can be resolved by xShadowStrike soon. Thanks.
You're able to see nametags when someone is invisible. Here is what people see when someone else is invisible. https://imgur.com/a/pCtwW
I intentionally took the picture when potion particles would appear. And what Tehnoobplanet said in game chat was just screwing around with you (People tend to do it a lot). There is no favoritism in this.