If you have suffixes and prefixes enabled, and you don't have a plugin that supports these, your name will be repeated multiple times in the various places that a name is shown, examples:

(18:32:05) MinecraftBot: <AzelphurAzelphurAzelphurAzelphurAzelphur>: Hello, world! 13:34:03 [INFO] <MinecraftBotMinecraftBotMinecraftBotMinecraftBotMinecraftBot>: `MinecraftBot joined #Test.

Fixed :)