The other day I went bed mining. I picked up my ancient debris, and turned around to leave, when I got nailed in the side by an arrow. I turned and found a group of piglins at a Y value of 8. I killed them and went on my way. I was then joined by hoglins, skeletons, zombified piglins, and several other nether mobs. I ended up having to flee for my life back to the portal. 

Recreating this should be simple.