ConcurrentModificationException in ChatSearchingManager.filterMessages2 when using search feature

[m-afterlike]

Tried using the search feature and it crashed my game.

[18:00:44] [Client thread/FATAL]: Unreported exception thrown!
java.util.ConcurrentModificationException
at java.util.ArrayList$Itr.checkForComodification(ArrayList.java:911)
at java.util.ArrayList$Itr.next(ArrayList.java:861)
at org.polyfrost.chatting.chat.ChatSearchingManager.filterMessages2(ChatSearchingManager.kt:71)
at org.polyfrost.chatting.chat.ChatSearchingManager.filterMessages(ChatSearchingManager.kt:39)
at net.minecraft.client.gui.GuiNewChat.handler$zop000$startCaptureHeight(SourceFile:635)

Minecraft version: 1.8.9
Java version: 1.8.0_452