Setspawn error

[18:47:20 WARN]: [FabledSkyBlock] Plugin FabledSkyBlock vBuild-73 generated an exception while executing task 709087
java.lang.IllegalStateException: Asynchronous entity add!
        at org.spigotmc.AsyncCatcher.catchOp(AsyncCatcher.java:14) ~[spigot-1.13.2.jar:git-Spigot-f09662d-f40143e]
        at net.minecraft.server.v1_13_R2.World.addEntity(World.java:906) ~[spigot-1.13.2.jar:git-Spigot-f09662d-f40143e]
        at net.minecraft.server.v1_13_R2.WorldServer.addEntity(WorldServer.java:917) ~[spigot-1.13.2.jar:git-Spigot-f09662d-f40143e]
        at net.minecraft.server.v1_13_R2.World.addEntity(World.java:902) ~[spigot-1.13.2.jar:git-Spigot-f09662d-f40143e]
        at net.minecraft.server.v1_13_R2.Block.a(Block.java:438) ~[spigot-1.13.2.jar:git-Spigot-f09662d-f40143e]
        at net.minecraft.server.v1_13_R2.Block.dropNaturally(Block.java:417) ~[spigot-1.13.2.jar:git-Spigot-f09662d-f40143e]
        at org.bukkit.craftbukkit.v1_13_R2.block.CraftBlock.breakNaturally(CraftBlock.java:527) ~[spigot-1.13.2.jar:git-Spigot-f09662d-f40143e]
        at me.goodandevil.skyblock.command.commands.island.SetSpawnCommand.onCommandByPlayer(SetSpawnCommand.java:96) ~[?:?]
        at me.goodandevil.skyblock.command.CommandManager$1.run(CommandManager.java:258) ~[?:?]
        at org.bukkit.craftbukkit.v1_13_R2.scheduler.CraftTask.run(CraftTask.java:81) ~[spigot-1.13.2.jar:git-Spigot-f09662d-f40143e]
        at org.bukkit.craftbukkit.v1_13_R2.scheduler.CraftAsyncTask.run(CraftAsyncTask.java:52) [spigot-1.13.2.jar:git-Spigot-f09662d-f40143e]
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [?:1.8.0_201]
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [?:1.8.0_201]
        at java.lang.Thread.run(Thread.java:748) [?:1.8.0_201]