Is Elder bugged or am I doing it wrong?

Sorry if this has already been answered, I haven't been able to find a solution. The short version is I was hoping to fight the Elder. I found this guide here:

https://www.reddit.com/r/pathofexile/comments/7ivc4g/short_guide_on_how_to_meet_the_elder/

So I did what it said, I fought all the guardians first, then I went to the map where it was "occupied by the elder", fought the boss, and... nothing. The Elder never appeared. To clarify, here is exactly what I did:

1. Fought the Eradicator (he dropped no loot, the elder just showed up at the end and drained him)
2. Fought the Enslaver (same as above)
3. Fought the Purifier (same as above)
4. Fought the Constrictor (same as above)
5. Went to the map where the elder was supposed to be. Fought the boss instead, Elder never showed.

So what did I do wrong? Is it just chance if I actually encounter him or not, despite saying he's there? If so, that kind of sucks?