Mobs not spawning correctly

New server running Direwolf20 1.10 pack, latest version
Additional plugins:
PurpleIRC - Forge Mod
Worldedit - Forge mod
LuckPerms
UltimateChat

I am using the Sponge Coremod bootstrap wrapper on launch to get AE2 to work.

The server is part of a BungeeCord network as well.

Problem:
Mobs sometimes will not spawn at all. When they do it is in limited numbers. I have not seen a single ghast in the nether. Blazes are few and far between, I can walk outside all night and maybe see 2-3 hostile mobs all night.

This persists through server restarts.What could be the issue?