Program: 174676
Project: 174676
Buggy source:
@Override protected void actionPerformed(GuiButton button) throws IOException {
  EntityPlayer player=mc.player;
  IPlayerInformation playerInfo=player.getCapability(CapabilityPlayerInformation.PLAYER_INFORMATION,null);
  if (player != null && playerInfo != null && playerInfo.getSkillPoints() > 0) {
    if (button == plusStrength) {
      playerInfo.setStrengthStat(playerInfo.getStrengthStat() + 1);
      AttributeModifier strengthModifier=new AttributeModifier(UUID.fromString(PacketUpdateIncreaseStat.STRENGTH),"String_Node_Str",2 + (playerInfo.getStrengthStat() + playerInfo.getBonusStrengthStat()),1);
      if (player.getEntityAttribute(SharedMonsterAttributes.ATTACK_DAMAGE).getModifier(UUID.fromString(PacketUpdateIncreaseStat.STRENGTH)) != null) {
        player.getEntityAttribute(SharedMonsterAttributes.ATTACK_DAMAGE).removeModifier(UUID.fromString(PacketUpdateIncreaseStat.STRENGTH));
        player.getEntityAttribute(SharedMonsterAttributes.ATTACK_DAMAGE).applyModifier(strengthModifier);
      }
 else       player.getEntityAttribute(SharedMonsterAttributes.ATTACK_DAMAGE).applyModifier(strengthModifier);
      LostEclipse.LOGGER.info("String_Node_Str" + player.getEntityAttribute(SharedMonsterAttributes.ATTACK_DAMAGE).getAttributeValue());
      LostEclipse.network.sendToServer(new PacketUpdateIncreaseStat(1));
    }
 else     if (button == plusAgility)     LostEclipse.network.sendToServer(new PacketUpdateIncreaseStat(2));
 else     if (button == plusDexterity)     LostEclipse.network.sendToServer(new PacketUpdateIncreaseStat(3));
 else     if (button == plusIntelligence)     LostEclipse.network.sendToServer(new PacketUpdateIncreaseStat(4));
 else     if (button == plusWisdom)     LostEclipse.network.sendToServer(new PacketUpdateIncreaseStat(5));
 else     if (button == plusFortitude)     LostEclipse.network.sendToServer(new PacketUpdateIncreaseStat(6));
    playerInfo.setSkillPoints(playerInfo.getSkillPoints() - 1);
  }
}

Fixed version (ground truth):
@Override protected void actionPerformed(GuiButton button) throws IOException {
  EntityPlayer player=mc.player;
  IPlayerInformation playerInfo=player.getCapability(CapabilityPlayerInformation.PLAYER_INFORMATION,null);
  if (player != null && playerInfo != null && playerInfo.getSkillPoints() > 0) {
    if (button == plusStrength) {
      playerInfo.setStrengthStat(playerInfo.getStrengthStat() + 1);
      LostEclipse.network.sendToServer(new PacketUpdateIncreaseStat(1));
    }
 else     if (button == plusAgility) {
      playerInfo.setAgilityStat(playerInfo.getAgilityStat() + 1);
      LostEclipse.network.sendToServer(new PacketUpdateIncreaseStat(2));
    }
 else     if (button == plusDexterity) {
      playerInfo.setDexterityStat(playerInfo.getDexterityStat() + 1);
      LostEclipse.network.sendToServer(new PacketUpdateIncreaseStat(3));
    }
 else     if (button == plusIntelligence) {
      playerInfo.setIntelligenceStat(playerInfo.getIntelligenceStat() + 1);
      LostEclipse.network.sendToServer(new PacketUpdateIncreaseStat(4));
    }
 else     if (button == plusWisdom) {
      playerInfo.setWisdomStat(playerInfo.getWisdomStat() + 1);
      LostEclipse.network.sendToServer(new PacketUpdateIncreaseStat(5));
    }
 else     if (button == plusFortitude) {
      playerInfo.setFortitudeStat(playerInfo.getFortitudeStat() + 1);
      LostEclipse.network.sendToServer(new PacketUpdateIncreaseStat(6));
    }
    playerInfo.setSkillPoints(playerInfo.getSkillPoints() - 1);
    PlayerStatHelper.updateAttributes(player);
  }
}