Program: 12623
Project: 12623
Buggy source:
@SubscribeEvent(priority=EventPriority.HIGHEST) public void onPlayerInteract(PlayerInteractEvent.RightClickBlock event){
  if (Configs.autoConvertGlasBottles) {
    if (event.getWorld().getWorldBorder().contains(event.getPos())) {
      ItemStack stack=event.getItemStack();
      if (!ItemStackUtil.isEmpty(stack) && stack.getItem().equals(Items.GLASS_BOTTLE) && ItemStackUtil.getCount(stack) == 1) {
        Block block=event.getWorld().getBlockState(event.getPos()).getBlock();
        boolean flag=false;
        if (block instanceof IFluidTank) {
          VampirismMod.log.d("String_Node_Str","String_Node_Str",block.getClass());
          if (ModFluids.blood.equals(((IFluidTank)block).getFluid())) {
            flag=true;
          }
        }
 else         if (block instanceof ITileEntityProvider) {
          TileEntity entity=event.getWorld().getTileEntity(event.getPos());
          if (entity != null && entity.hasCapability(CapabilityFluidHandler.FLUID_HANDLER_CAPABILITY,event.getFace())) {
            net.minecraftforge.fluids.capability.IFluidHandler fluidHandler=entity.getCapability(CapabilityFluidHandler.FLUID_HANDLER_CAPABILITY,event.getFace());
            FluidStack drain=fluidHandler.drain(new FluidStack(ModFluids.blood,1000),false);
            if (drain != null && drain.amount >= BloodBottleFluidHandler.MULTIPLIER) {
              flag=true;
            }
          }
          if (flag && block instanceof BlockAltarInspiration) {
            flag=false;
          }
          if (flag && block instanceof BlockBloodContainer) {
            flag=event.getEntityPlayer().isSneaking();
          }
        }
        if (flag) {
          stack.deserializeNBT(new ItemStack(ModItems.bloodBottle).serializeNBT());
        }
      }
    }
  }
}

Fixed version (ground truth):
@SubscribeEvent(priority=EventPriority.HIGHEST) public void onPlayerInteract(PlayerInteractEvent.RightClickBlock event){
  if (event.getWorld().getWorldBorder().contains(event.getPos())) {
    ItemStack heldStack=event.getItemStack();
    if (!ItemStackUtil.isEmpty(heldStack) && ItemStackUtil.getCount(heldStack) == 1) {
      boolean glasBottle=Items.GLASS_BOTTLE.equals(heldStack.getItem());
      boolean bloodBottle=ModItems.bloodBottle.equals(heldStack.getItem());
      if (bloodBottle || (glasBottle && Configs.autoConvertGlasBottles)) {
        Block block=event.getWorld().getBlockState(event.getPos()).getBlock();
        boolean convert=false;
        if (glasBottle && block instanceof ITileEntityProvider) {
          TileEntity entity=event.getWorld().getTileEntity(event.getPos());
          if (entity != null && entity.hasCapability(CapabilityFluidHandler.FLUID_HANDLER_CAPABILITY,event.getFace())) {
            net.minecraftforge.fluids.capability.IFluidHandler fluidHandler=entity.getCapability(CapabilityFluidHandler.FLUID_HANDLER_CAPABILITY,event.getFace());
            FluidStack drain=fluidHandler.drain(new FluidStack(ModFluids.blood,1000),false);
            if (drain != null && drain.amount >= BloodBottleFluidHandler.MULTIPLIER) {
              convert=true;
            }
            if (convert && block instanceof BlockAltarInspiration) {
              convert=false;
            }
            if (convert && block instanceof BlockBloodContainer) {
              convert=event.getEntityPlayer().isSneaking();
            }
          }
        }
        if ((bloodBottle || convert) && block instanceof BlockBloodContainer) {
          event.setUseBlock(Event.Result.ALLOW);
        }
        if (convert) {
          heldStack.deserializeNBT(new ItemStack(ModItems.bloodBottle).serializeNBT());
        }
      }
    }
  }
}