Items with more than one word in the name aren't being recognized

[onthespence]

For some odd reason items with only one word in the name such as Aquarium, or Creeper, can drop heads or be crafted, but when I try to get blocks such as Mini Pumpkin or crafting an Alex Plush it says things such as this in the console:

It also says this when I first boot up the server as well:
"[DecorHeads] Can not set net.minecraft.world.item.component.ResolvableProfile field org.bukkit.craftbukkit.inventory.CraftMetaSkull.profile to com.mojang.authlib.GameProfile"