Good morning or good evening ! I come to you because I need help! I currently have a server under the last stable version of SpongeForge to which I put my modpack. After a while I remembered that I did not see mobs about the mod “Primitive Mobs”, so I tried to find the problem, I looked if the same problem in solo, resulat? Not everything is ok that spawn! So I did some research on the mod creator’s page and came across this comment
"Hello, first of all, you’ve created something really cool.
Sponge, a spawn, a spawn, a spawn in a natural way, I have reviewed everything and I do not find the reason, with an egg from the creative you can spawn, but do not appear as you walk through the server …
EDIT:
I can confirm, after several tests I have discovered that sponge is the cause of death.
Last edited by Marshall_Off: Apr 20, 2019 "
As I come to you, you must certainly realize it but after some tests, yes it is Sponge who blocks the spawns of these mobs. My question is: Is this a Sponge bug? Is there an option in sponge configs files to fix this problem? Sorry for my bad English 
Hoping that you have a solution !!
thx, u dont know if more mods have that spwan problem ?