Could not pass event PlayerQuitEvent to FirstJoinPlus v2.4.1 [Spigot 1.11.2 / JDK 1.8.0_121 / Debian 8.7]

[Refalm]

Getting a weird error and perhaps some random disconnects:
[16:18:05] [Server thread/INFO]: YouFeaq lost connection: Internal Exception: java.io.IOException: Error while read(...): Connection reset by peer [16:18:05] [Server thread/ERROR]: Could not pass event PlayerQuitEvent to FirstJoinPlus v2.4.1 org.bukkit.event.EventException at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:306) ~[spigot.jar:git-Spigot-96235ab-2aa5ac6] at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62) ~[spigot.jar:git-Spigot-96235ab-2aa5ac6] at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:502) [spigot.jar:git-Spigot-96235ab-2aa5ac6] at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:487) [spigot.jar:git-Spigot-96235ab-2aa5ac6] at net.minecraft.server.v1_11_R1.PlayerList.disconnect(PlayerList.java:379) [spigot.jar:git-Spigot-96235ab-2aa5ac6] at net.minecraft.server.v1_11_R1.PlayerConnection.a(PlayerConnection.java:1055) [spigot.jar:git-Spigot-96235ab-2aa5ac6] at net.minecraft.server.v1_11_R1.NetworkManager.handleDisconnection(NetworkManager.java:316) [spigot.jar:git-Spigot-96235ab-2aa5ac6] at net.minecraft.server.v1_11_R1.ServerConnection.c(ServerConnection.java:174) [spigot.jar:git-Spigot-96235ab-2aa5ac6] at net.minecraft.server.v1_11_R1.MinecraftServer.D(MinecraftServer.java:842) [spigot.jar:git-Spigot-96235ab-2aa5ac6] at net.minecraft.server.v1_11_R1.DedicatedServer.D(DedicatedServer.java:399) [spigot.jar:git-Spigot-96235ab-2aa5ac6] at net.minecraft.server.v1_11_R1.MinecraftServer.C(MinecraftServer.java:678) [spigot.jar:git-Spigot-96235ab-2aa5ac6] at net.minecraft.server.v1_11_R1.MinecraftServer.run(MinecraftServer.java:576) [spigot.jar:git-Spigot-96235ab-2aa5ac6] at java.lang.Thread.run(Thread.java:745) [?:1.8.0_121] Caused by: java.lang.NullPointerException at java.lang.String.replace(String.java:2240) ~[?:1.8.0_121] at com.chaseoes.firstjoinplus.utilities.Utilities.replaceVariables(Utilities.java:161) ~[?:?] at com.chaseoes.firstjoinplus.PlayerListeners.onPlayerQuit(PlayerListeners.java:72) ~[?:?] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_121] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_121] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_121] at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_121] at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:302) ~[spigot.jar:git-Spigot-96235ab-2aa5ac6] ... 12 more [16:18:05] [Server thread/INFO]: YouFeaq left the game