https://pastebin.com/Qnutna2c

Unsure as how to replicate this, but I have been reporting all errors I find in my modpack as of late for stability.

Description: Error executing task

java.util.concurrent.ExecutionException: java.lang.NullPointerException
at java.util.concurrent.FutureTask.report(Unknown Source)
at java.util.concurrent.FutureTask.get(Unknown Source)
at net.minecraft.util.Util.runTask(SourceFile:531)
at net.minecraft.client.Minecraft.runGameLoop(Minecraft.java:1087)
at net.minecraft.client.Minecraft.run(Minecraft.java:3941)
at net.minecraft.client.main.Main.main(SourceFile:123)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at net.minecraft.launchwrapper.Launch.launch(Launch.java:135)
at net.minecraft.launchwrapper.Launch.main(Launch.java:28)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.multimc.onesix.OneSixLauncher.launchWithMainClass(OneSixLauncher.java:196)
at org.multimc.onesix.OneSixLauncher.launch(OneSixLauncher.java:231)
at org.multimc.EntryPoint.listen(EntryPoint.java:143)
at org.multimc.EntryPoint.main(EntryPoint.java:34)
Caused by: java.lang.NullPointerException
at com.attributestudios.wolfarmor.common.network.packets.WolfArmorCapabilityDataMessage.process(WolfArmorCapabilityDataMessage.java:47)
at com.attributestudios.wolfarmor.common.network.MessageBase$1.run(MessageBase.java:46)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at net.minecraft.util.Util.runTask(SourceFile:529)
... 17 more

Even on a single player enviroment, seems like exiting the current save throws this about 50/50 of the time. Not sure if this really causes any true issues, but it will crash the client.

I have a null pointer issue as well. Vanillafix detects it and proceeds to spam error logs from the wolf armor mod "crash" happening over and over the moment I disconnect from my server through the disconnect button (timing out, server closing, etc. do not cause this issue for some reason.) It persists even if I load back into the server, only closing and re-opening Minecraft entirely seems to fix it.
crash-2018-09-03_01.01.59-client.txt