90% of the top junglers on op.gg play kha with a 60%+ winrate

I mean that is what happens when the Jungle is gutted so bad that you need a champion good at dueling and at ganking.

Kha one shots your carries without isolation damage that's how overtuned he is.

Rank 1 on NA has a 40% winrate with Kha https://na.op.gg/summoner/userName=benice2eachother

So top players have top winrates with a A tier champion.

What's the issue?

Also, can you give a link to those stats?

Globally or just NA?

He was buffed hard for worlds, despite being an already amazing pick in solo queue, and riot never thought to revert him back. That's the reason why. He got buff after buff so he would see competitive play.