Error in console please help!

I tried Dev build and recommended build... none of these fix this error. Please help how do u fix this?

03.08 15:33:54 [Server] WARN Unknown target reason, please report on the issue tracker 03.08 15:33:54 [Server] INFO java.lang.Exception 03.08 15:33:54 [Server] INFO at net.minecraft.server.v1_8_R3.EntityInsentient.setGoalTarget(EntityInsentient.java:102) [spigot45.jar:git-Spigot-5f38d38-12698ea] 03.08 15:33:54 [Server] INFO at...

Error in console please help!