An animator at Toei just said they've just done three episodes at once. The last time the anime team made sure to make concurrent episodes was when they had to make sure to coordinate the episodes and that was of course Luffy vs kaido where the flow from one episode to another was required
The fact that he's saying he's just finished then these are episodes that should've aired like 1 or so months from now since that's how far back the An episode that's just aired was made.
Therefore he's talking about like episode 933-935 or so... And Zoro vs Killer is supposed to happen around Episode 934
Therefore Zoro vs Killer has been animated