[08:29:51 ERROR]: "Silently" catching entity tracking error.
net.minecraft.server.v1_7_R1.ReportedException: Adding entity to track
        at net.minecraft.server.v1_7_R1.EntityTracker.addEntity(EntityTracker.java:122) [spigot.jar:git-Spigot-1222]
        at net.minecraft.server.v1_7_R1.EntityTracker.track(EntityTracker.java:73) [spigot.jar:git-Spigot-1222]
        at net.minecraft.server.v1_7_R1.WorldManager.a(WorldManager.java:18) [spigot.jar:git-Spigot-1222]
        at net.minecraft.server.v1_7_R1.World.a(World.java:1004) [spigot.jar:git-Spigot-1222]
        at net.minecraft.server.v1_7_R1.WorldServer.a(WorldServer.java:816) [spigot.jar:git-Spigot-1222]
        at net.minecraft.server.v1_7_R1.World.addEntity(World.java:997) [spigot.jar:git-Spigot-1222]
        at net.minecraft.server.v1_7_R1.World.addEntity(World.java:924) [spigot.jar:git-Spigot-1222]
        at net.minecraft.server.v1_7_R1.PlayerList.repositionEntity(PlayerList.java:750) [spigot.jar:git-Spigot-1222]
        at net.minecraft.server.v1_7_R1.Entity.teleportTo(Entity.java:1831) [spigot.jar:git-Spigot-1222]
        at org.bukkit.craftbukkit.v1_7_R1.entity.CraftEntity.teleport(CraftEntity.java:211) [spigot.jar:git-Spigot-1222]
        at org.bukkit.craftbukkit.v1_7_R1.entity.CraftLivingEntity.teleport(CraftLivingEntity.java:365) [spigot.jar:git-Spigot-1222]
        at org.bukkit.craftbukkit.v1_7_R1.entity.CraftEntity.teleport(CraftEntity.java:200) [spigot.jar:git-Spigot-1222]
        at net.citizensnpcs.api.npc.AbstractNPC.teleport(AbstractNPC.java:389) [citizens-2.0.11-SNAPSHOT.jar:?]
        at net.citizensnpcs.api.npc.AbstractNPC.teleport(AbstractNPC.java:414) [citizens-2.0.11-SNAPSHOT.jar:?]
        at net.aufdemrand.sentry.SentryInstance.initialize(SentryInstance.java:1025) [Sentry.jar:?]
        at net.aufdemrand.sentry.SentryTrait.onSpawn(SentryTrait.java:126) [Sentry.jar:?]
        at net.citizensnpcs.npc.CitizensNPC.spawn(CitizensNPC.java:195) [citizens-2.0.11-SNAPSHOT.jar:?]
        at net.citizensnpcs.npc.CitizensNPC.load(CitizensNPC.java:113) [citizens-2.0.11-SNAPSHOT.jar:?]
        at net.citizensnpcs.api.npc.SimpleNPCDataStore.loadInto(SimpleNPCDataStore.java:55) [citizens-2.0.11-SNAPSHOT.jar:?]
        at net.citizensnpcs.Citizens$1.run(Citizens.java:274) [citizens-2.0.11-SNAPSHOT.jar:?]
        at org.bukkit.craftbukkit.v1_7_R1.scheduler.CraftTask.run(CraftTask.java:58) [spigot.jar:git-Spigot-1222]
        at org.bukkit.craftbukkit.v1_7_R1.scheduler.CraftScheduler.mainThreadHeartbeat(CraftScheduler.java:345) [spigot.jar:git-Spigot-1222]
        at net.minecraft.server.v1_7_R1.MinecraftServer.u(MinecraftServer.java:583) [spigot.jar:git-Spigot-1222]
        at net.minecraft.server.v1_7_R1.DedicatedServer.u(DedicatedServer.java:273) [spigot.jar:git-Spigot-1222]
        at net.minecraft.server.v1_7_R1.MinecraftServer.t(MinecraftServer.java:540) [spigot.jar:git-Spigot-1222]
        at net.minecraft.server.v1_7_R1.MinecraftServer.run(MinecraftServer.java:446) [spigot.jar:git-Spigot-1222]
        at net.minecraft.server.v1_7_R1.ThreadServerApplication.run(SourceFile:617) [spigot.jar:git-Spigot-1222]
Caused by: java.lang.IllegalStateException: Entity is already tracked!
        at net.minecraft.server.v1_7_R1.EntityTracker.addEntity(EntityTracker.java:102) ~[spigot.jar:git-Spigot-1222]
        ... 26 more
[08:29:51 INFO]: [Citizens] Loaded 69 NPCs (? spawned).