Chromaggus Despawning 3secs after Aggro

[Hexuas1]

Not sure if this is a bug. But I was recently trying to solo as much of BWL as possible. I've reached Chromaggus but everytime I try to aggro him he just keeps despawning 3 seconds after pull. Not sure but maybe this has something to do with skipping Ebonroc.

Did anyone experience something like this before? If so, did you ever find a solution?

[Shred]

Make sure you have killed all previous bosses before engaging Chromaggus.