Program: 174691
Project: 174691
Buggy source:
public static void register(){
  CapabilityManager.INSTANCE.register(IPlayerInformation.class,new Capability.IStorage<IPlayerInformation>(){
    @Override public NBTBase writeNBT(    Capability<IPlayerInformation> capability,    IPlayerInformation instance,    EnumFacing side){
      NBTTagCompound nbt=new NBTTagCompound();
      nbt.setInteger("String_Node_Str",instance.getPlayerClass());
      nbt.setInteger("String_Node_Str",instance.getPlayerLevel());
      nbt.setInteger("String_Node_Str",instance.getPlayerExperience());
      nbt.setInteger("String_Node_Str",instance.getSkillPoints());
      nbt.setInteger("String_Node_Str",instance.getStrengthStat());
      nbt.setInteger("String_Node_Str",instance.getAgilityStat());
      nbt.setInteger("String_Node_Str",instance.getDexterityStat());
      nbt.setInteger("String_Node_Str",instance.getIntelligenceStat());
      nbt.setInteger("String_Node_Str",instance.getWisdomStat());
      nbt.setInteger("String_Node_Str",instance.getFortitudeStat());
      return nbt;
    }
    @Override public void readNBT(    Capability<IPlayerInformation> capability,    IPlayerInformation instance,    EnumFacing side,    NBTBase nbt){
      NBTTagCompound compound=(NBTTagCompound)nbt;
      instance.setPlayerClass(compound.getInteger("String_Node_Str"));
      instance.setPlayerLevel(compound.getInteger("String_Node_Str"));
      instance.setPlayerExperience(compound.getInteger("String_Node_Str"));
      instance.setSkillPoints(compound.getInteger("String_Node_Str"));
      instance.setStrengthStat(compound.getInteger("String_Node_Str"));
      instance.setAgilityStat(compound.getInteger("String_Node_Str"));
      instance.setDexterityStat(compound.getInteger("String_Node_Str"));
      instance.setIntelligenceStat(compound.getInteger("String_Node_Str"));
      instance.setWisdomStat(compound.getInteger("String_Node_Str"));
      instance.setFortitudeStat(compound.getInteger("String_Node_Str"));
    }
  }
,() -> new PlayerInformation(null));
  MinecraftForge.EVENT_BUS.register(new EventHandler());
}

Fixed version (ground truth):
public static void register(){
  CapabilityManager.INSTANCE.register(IPlayerInformation.class,new Capability.IStorage<IPlayerInformation>(){
    @Override public NBTBase writeNBT(    Capability<IPlayerInformation> capability,    IPlayerInformation instance,    EnumFacing side){
      NBTTagCompound nbt=new NBTTagCompound();
      nbt.setInteger("String_Node_Str",instance.getPlayerClass());
      nbt.setInteger("String_Node_Str",instance.getPlayerLevel());
      nbt.setInteger("String_Node_Str",instance.getPlayerExperience());
      nbt.setInteger("String_Node_Str",instance.getSkillPoints());
      nbt.setInteger("String_Node_Str",instance.getStrengthStat());
      nbt.setInteger("String_Node_Str",instance.getAgilityStat());
      nbt.setInteger("String_Node_Str",instance.getDexterityStat());
      nbt.setInteger("String_Node_Str",instance.getIntelligenceStat());
      nbt.setInteger("String_Node_Str",instance.getWisdomStat());
      nbt.setInteger("String_Node_Str",instance.getFortitudeStat());
      nbt.setInteger("String_Node_Str",instance.getBonusStrengthStat());
      nbt.setInteger("String_Node_Str",instance.getBonusAgilityStat());
      nbt.setInteger("String_Node_Str",instance.getBonusDexterityStat());
      nbt.setInteger("String_Node_Str",instance.getBonusIntelligenceStat());
      nbt.setInteger("String_Node_Str",instance.getBonusWisdomStat());
      nbt.setInteger("String_Node_Str",instance.getBonusFortitudeStat());
      return nbt;
    }
    @Override public void readNBT(    Capability<IPlayerInformation> capability,    IPlayerInformation instance,    EnumFacing side,    NBTBase nbt){
      NBTTagCompound compound=(NBTTagCompound)nbt;
      instance.setPlayerClass(compound.getInteger("String_Node_Str"));
      instance.setPlayerLevel(compound.getInteger("String_Node_Str"));
      instance.setPlayerExperience(compound.getInteger("String_Node_Str"));
      instance.setSkillPoints(compound.getInteger("String_Node_Str"));
      instance.setStrengthStat(compound.getInteger("String_Node_Str"));
      instance.setAgilityStat(compound.getInteger("String_Node_Str"));
      instance.setDexterityStat(compound.getInteger("String_Node_Str"));
      instance.setIntelligenceStat(compound.getInteger("String_Node_Str"));
      instance.setWisdomStat(compound.getInteger("String_Node_Str"));
      instance.setFortitudeStat(compound.getInteger("String_Node_Str"));
      instance.setBonusStrengthStat(compound.getInteger("String_Node_Str"));
      instance.setBonusAgilityStat(compound.getInteger("String_Node_Str"));
      instance.setBonusDexterityStat(compound.getInteger("String_Node_Str"));
      instance.setBonusIntelligenceStat(compound.getInteger("String_Node_Str"));
      instance.setBonusWisdomStat(compound.getInteger("String_Node_Str"));
      instance.setBonusFortitudeStat(compound.getInteger("String_Node_Str"));
    }
  }
,() -> new PlayerInformation(null));
  MinecraftForge.EVENT_BUS.register(new EventHandler());
}