Noob question regarding Dclone kill in Chaos via opening seals

Hey, I just realized I read something long time ago about killing dclone by poping seals in

Chaos Sanctuary.

So I decided to give it a try. Because I dont wanna be dependent on Dclone killers.

So what I did:

1) I TP to Chaos and clear areas around pentagram and seals (for my own safety).
2) I chose to spawn Dclone instead of

Infector of Souls and I opened both seals there (seal which spawns

Infector of Souls as 2nd - I didnt want to get swarmed by his minions, but they didnt spawned - only Dclone did).
3) I went to kill

Lord De Seis and last one I killed was

Grand Vizier of Chaos (I opened only seal which spawns him).
4) When

Lord De Seis and

Grand Vizier of Chaos were slain. I remembered farming guide in Chaos - before opening last seal you should fast TP through entire location to get drop from all the monsters when opening last seal - clearing entire location. So I checked Dclone and he was still there, after I saw him and launched few attacks on him (as saying "hello give me 20/20/10" - that didnt work either )
5) I quickly TP to last seal and opened it. But Dclone was still alive.

After opening last seal I didnt get typical Diablo speech, and it didnt clear entire area. After random smiter from the internet helped me kill Dclone. I just left the game without noticing if normal Diablo spawned or not)

Was my moves in wrong order? Or it has been fixed?

Haven't tried it in ages but I believe it has been fixed (at least plenty of folks claimed it was) which would be somewhat confirmed by you only spawning dclone from that seal.

It used to be that you'd clear 2 seals the normal way and then hold on for the 3rd set until after the walk is triggered. If you open that, you would then not get DClone but DClone AND the seal boss. Once you kill the seal boss, everything in CS (including DClone) would die as it always does.

If you now don't have a 3rd seal boss because he is fully replaced by dclone, you don't kill all 3 and CS is never nuked.

Thanks !

Oh, I miss the days of Shenk-killing DC

I once cleared all the seal bosses and just as when Big D was about to pop the walk happened and ...well..quest cannot complete