Hi! Forgive me in advance for my english. The problem: Sometimes players can not kill mobs. Mobs behave as usual: walk, attack, burn and die. But the player sometimes can not kill. As if they do not "stand out". Bug treated rejoining the server or sometimes (!) By changing the instrument in the hand. It is noticed that sometimes you can not kill a specific mob from the crowd. The data server: craftbukkit-1.4.7-R1.0 Plugins (34): TimTheEnchanter, MineConomy, SimpleAFK, Minequery, WorldEdit, FrameProtect, GiveAll, CommandBook, EasyColors, Vault, PermissionsEx, Multiverse-Core, LogBlock, MyHome, LWC, WorldGuard, PvPTimer, SignColours, dynmap, MinecraftBot, Dynmap -WorldGuard, MineBackup, LokiBan, EndReset, SuperKits, OpenInv, ZavAutoMessager, ColorMe, Modifyworld, ChunkSpawnerLimiter, WorldBorder, ChatManager, Multiverse-Portals, SignShop 12Gb RAM DDR3 AMD Phenom(tm) II X4 975 Processor 500ГБ HDD 10 000 /sec java version "1.7.0_17" ubuntu server 12.04 No mods. Customers usually with optifine + minemap. Downloads server are maximal and do not exceed 30-50%. With the internet problems just not noticed. Feels like - a problem in the client Help me please. Thank you.