UltraCube: crash when clicking on steam ingredient

[pyrachi]

Problem Description

With the UltraCube mod enabled, immediately after clicking on one of the steam ingredients in the GUI to add a recipe, the following crash occurs:

The mod Factory Planner (1.1.78) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event factoryplanner::Custom event (ID 282)
__factoryplanner__/backend/data/Machine.lua:62: attempt to index field '?' (a nil value)
stack traceback:
	__factoryplanner__/backend/data/Machine.lua:62: in function 'normalize_fuel'
	__factoryplanner__/backend/data/Line.lua:100: in function 'change_machine_to_proto'
	__factoryplanner__/backend/data/Line.lua:151: in function 'change_machine_to_default'
	__factoryplanner__/ui/dialogs/recipe_dialog.lua:94: in function 'attempt_adding_line'
	__factoryplanner__/ui/dialogs/recipe_dialog.lua:258: in function 'early_abort'
	__factoryplanner__/ui/base/modal_dialog.lua:154: in function 'enter'
	__factoryplanner__/ui/event_handler.lua:209: in function <__factoryplanner__/ui/event_handler.lua:189>
	[C]: in function 'raise_event'
	__factoryplanner__/util/raise.lua:20: in function 'open_dialog'
	__factoryplanner__/ui/main/item_boxes.lua:11: in function 'add_recipe'
	__factoryplanner__/ui/main/item_boxes.lua:161: in function 'handler'
	__factoryplanner__/ui/event_handler.lua:157: in function <__factoryplanner__/ui/event_handler.lua:114>
stack traceback:
	[C]: in function 'raise_event'
	__factoryplanner__/util/raise.lua:20: in function 'open_dialog'
	__factoryplanner__/ui/main/item_boxes.lua:11: in function 'add_recipe'
	__factoryplanner__/ui/main/item_boxes.lua:161: in function 'handler'
	__factoryplanner__/ui/event_handler.lua:157: in function <__factoryplanner__/ui/event_handler.lua:114>

factorio-current.log Ultracube.zip

Reproduction

1. Load save
2. Open Factory Planner
3. In Factory Planner preferences set the default boiler to the vanilla boiler.
4. Click on steam ingredient in upper right corner.

[pyrachi]

I cross-posted this to the UltraCube mod. https://mods.factorio.com/mod/Ultracube/discussion/65ac18503117b0345963cbf6

Per the discussion there, the crash only occurs when the vanilla boiler is selected in the Factory Planner preferences. Switching to UltraCube's boiler eliminates the crash.