16:45:46 FATAL]: Error executing task
java.util.concurrent.ExecutionException: java.lang.AssertionError: TRAP
        at java.util.concurrent.FutureTask.report(Unknown Source) ~[?:1.8.0_111]
        at java.util.concurrent.FutureTask.get(Unknown Source) ~[?:1.8.0_111]
        at net.minecraft.server.v1_11_R1.SystemUtils.a(SourceFile:47) [server.jar:git-Spigot-7d78b81-7e19325]
        at net.minecraft.server.v1_11_R1.MinecraftServer.D(MinecraftServer.java:739) [server.jar:git-Spigot-7d78b81-7e19325]
        at net.minecraft.server.v1_11_R1.DedicatedServer.D(DedicatedServer.java:399) [server.jar:git-Spigot-7d78b81-7e19325]
        at net.minecraft.server.v1_11_R1.MinecraftServer.C(MinecraftServer.java:675) [server.jar:git-Spigot-7d78b81-7e19325]
        at net.minecraft.server.v1_11_R1.MinecraftServer.run(MinecraftServer.java:574) [server.jar:git-Spigot-7d78b81-7e19325]
        at java.lang.Thread.run(Unknown Source) [?:1.8.0_111]
Caused by: java.lang.AssertionError: TRAP
        at net.minecraft.server.v1_11_R1.ItemStack.F(ItemStack.java:94) ~[server.jar:git-Spigot-7d78b81-7e19325]
        at net.minecraft.server.v1_11_R1.ItemStack.setCount(ItemStack.java:822) ~[server.jar:git-Spigot-7d78b81-7e19325]
        at net.minecraft.server.v1_11_R1.PlayerInteractManager.a(PlayerInteractManager.java:403) ~[server.jar:git-Spigot-7d78b81-7e19325]
        at net.minecraft.server.v1_11_R1.PlayerConnection.a(PlayerConnection.java:957) ~[server.jar:git-Spigot-7d78b81-7e19325]
        at net.minecraft.server.v1_11_R1.PacketPlayInBlockPlace.a(PacketPlayInBlockPlace.java:26) ~[server.jar:git-Spigot-7d78b81-7e19325]
        at net.minecraft.server.v1_11_R1.PacketPlayInBlockPlace.a(PacketPlayInBlockPlace.java:1) ~[server.jar:git-Spigot-7d78b81-7e19325]
        at net.minecraft.server.v1_11_R1.PlayerConnectionUtils$1.run(SourceFile:13) ~[server.jar:git-Spigot-7d78b81-7e19325]
        at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) ~[?:1.8.0_111]
        at java.util.concurrent.FutureTask.run(Unknown Source) ~[?:1.8.0_111]
        at net.minecraft.server.v1_11_R1.SystemUtils.a(SourceFile:46) ~[server.jar:git-Spigot-7d78b81-7e19325]
        ... 5 more