Minecraft plugin error message while chatting?

Hello if I write something in the chat I get this error message

[17:47:27 ERROR]: Could not pass event AsyncPlayerChatEvent to CBSystem v1.0

org.bukkit.event.EventException

at org.bukkit.plugin.java.JavaPluginLoader $ 1.execute (JavaPluginLoader.java:310) ~ [spigot.jar: git-spigot-db6de12-18fbb24]

at org.bukkit.plugin.RegisteredListener.callEvent (RegisteredListener.java:62) ~ [spigot.jar: git-spigot-db6de12-18fbb24]

at org.bukkit.plugin.SimplePluginManager.fireEvent (SimplePluginManager.java:502) [spigot.jar: git-spigot-db6de12-18fbb24]

at org.bukkit.plugin.SimplePluginManager.callEvent (SimplePluginManager.java: 484) [spigot.jar: git-spigot-db6de12-18fbb24]

at net.minecraft.server.v1_8_R3.PlayerConnection.chat (PlayerConnection.java:1084) [spigot.jar: git-spigot-db6de12-18fbb24]

at net.minecraft.server.v1_8_R3.PlayerConnection.a (PlayerConnection.java:1022) [spigot.jar: git-spigot-db6de12-18fbb24]

at net.minecraft.server.v1_8_R3.PacketPlayInChat $ 1.run (PacketPlayInChat.java:39) [spigot.jar: git-spigot-db6de12-18fbb24]

at java.util.concurrent.Executors $ RunnableAdapter.call (Unknown Source) [?: 1.8.0_201]

at java.util.concurrent.FutureTask.run (Unknown Source) [?: 1.8.0_201]

at java.util.concurrent.ThreadPoolExecutor.runWorker (Unknown Source) [?: 1.8.0_201]

at java.util.concurrent.ThreadPoolExecutor $ Worker.run (Unknown Source) [?: 1.8.0_201]

at java.lang.Thread.run (Unknown Source) [?: 1.8.0_201]

Caused by: java.util.UnknownFormatConversionException: Conversion = ''

at org.bukkit.event.player.AsyncPlayerChatEvent.setFormat (AsyncPlayerChatEvent.java:100) ~ [spigot.jar: git-spigot-db6de12-18fbb24]

at r.x.x.x.b.ALLATORIxDEMO (k: 463) ~ [?:?]

at r.x.x.x.b.onChat (k: 543) ~ [?:?]

at sun.reflect.NativeMethodAccessorImpl.invoke0 (Native Method) ~ [?: 1.8.0_201]

at sun.reflect.NativeMethodAccessorImpl.invoke (Unknown Source) ~ [?: 1.8.0_201]

at sun.reflect.DelegatingMethodAccessorImpl.invoke (Unknown Source) ~ [?: 1.8.0_201]

at java.lang.reflect.Method.invoke (Unknown Source) ~ [?: 1.8.0_201]

at org.bukkit.plugin.java.JavaPluginLoader $ 1.execute (JavaPluginLoader.java:306) ~ [spigot.jar: git-spigot-db6de12-18fbb24]

… 11 more

What does this mean? So I've come so far: Something is wrong with CBSystem v1.0

Which version does the server have? Is this the CBSystem of Patty? (Can find out, if you write #Patty in the chat)

Yeah this is the one of Patty my server is running on version 1.8

Do you have discord or something similar? Could show you an alternative to the CBSystem. With such a mistake, you'd really have to contact Patty

Can you send a link here? So from the plugin?

No. Is programmed by me and I do not want to make the thing available to everyone.

If necessary, you could also install the plugins from which the CBSystem was "tinkered":

A chat system

A prefix system

Essentials

The edge plugin

That should be all