Some mobs don't spawn

[Ender_Sca770]

Inspired by a video, i created a world that is only ice spikes biome, and then put it in minehut and set it as the main world, to play with my friends; i added the plugins EssentialsX and EssentialsSpawn since i needed to put the world as the main one, and Armor Stand Editor just for fun, so I don't think the problem is caused by plugins...
So the problem is: every mob spawns normally, we could even start a villager farm, and mob spawners (i mean the cages) work, but those mobs that spawn via probability, and i mean the wandering trader, the phantoms and the pillager patrols, don't spawn, they all spawned only once and i'm pretty sure in the same minecraft day; phantoms probably don't spawn because we sleep every night, but the trader and patrols do NEVER spawn, even after hours and hours of gameplay! Can anybody tell me what i could have done wrong?

[Skray]

Unlucky maybe

[CoolProgrammer]

Hey there.

The mobs that never spawn might be because of the biome. Some mobs will only spawn in a specific biomes.