Hello, I've just gotten back into Craft so maybe they've changed something giving me this issue.
I found a zombie spawner and made an XP farm out of it. I used the water elevator design. Dark 9x9 room, water brings them to the elevator, horizontal tunnel and then 19 block drop. Simple. I added a 1 block high hole at the base of the elevator that takes the babies into a lava pit.
But, when the killing floor fills with 20 zombies or so, all new arrivals simply die upon impact. Nothing should be hurting them prior. I reduced the drop from 19 blocks to 15, no difference, except no it's harder to kill the surviving ones.
As soon as a clear the killing floor, the new arrivals magically survive...until it fills up to 20ish + zombies again. This makes my farm much less efficient. Any ideas are appreciated, thanks!!
To answer your issue, the PS4 version has a mob limit of 25. once you have hit that limit in the same area they will die. There is related google results to it, i found out the hard way when I built a massive pigman exp farm(but it works wonders for things like gold, as you get xp only when yu hit them, they still drop thier drops otherwise!)
Dang, that kinda blows. I guess getting a lot of xp will require babysitting the trap more. I had a skeleton xp farm back in the consoles equivilant of 1.9 Beta or so, that worked wonders. 20 mins of waiting was for sure a level 30 guarantee. The auto dying could be utilized with hoppers though so you could afk and they'll kill themselves and fill your chests with bones or whatever loot it is. Thanks for the reply!