(DragonAPI v33b) ReikaItemHelper.matchStacks(null, FlexibleIngredient.EMPTY) incorrectly returns false

[dalapo]

This has implications for adding custom recipes to various machines such as ReactorCraft's fluid synthesizer - recipes with empty ItemStacks (for example, a fluid with zero or one items) will be added, and show up in NEI, but not be processed by the machine.