PaperMC/paper-server/nms-patches/net/minecraft/world/entity/projectile/EntityFireballFireball.patch

--- a/net/minecraft/world/entity/projectile/EntityFireballFireball.java
+++ b/net/minecraft/world/entity/projectile/EntityFireballFireball.java
@@ -65,6 +65,6 @@
         super.readAdditionalSaveData(nbttagcompound);
         ItemStack itemstack = ItemStack.of(nbttagcompound.getCompound("Item"));
 
-        this.setItem(itemstack);
+        if (!itemstack.isEmpty()) this.setItem(itemstack); // CraftBukkit - SPIGOT-5474 probably came from bugged earlier versions
     }
 }