Zul Gurub cache of madness

I’m wondering if this is bugged? I have been farming this fight for months & have never once seen 3 of the bosses that spawn from this fight, I get the same 2 every time. Its ok if this is just bad luck, its just weird to me that I’ve run this so many times and have never seen the rest of the bosses. Its making me wonder if its just bugged for whatever reason and is only spawning 2 of the 5 potential boss fights? I’m looking for wooshoolay & I’ve literally never seen him out of the 50+ runs i’ve done on the cache of madness. Its just weird that’s the only reason I bring it up since they all have the same chance of spawning so I figured id bring it up in case it is bugged and i’m not just crazy lol.