(using version 18.1.0.1)
Getting the following LUA error when opening a crafting order (NPC order for Rune-Branded Kickers, in this case, but getting it for almost everything else as well). It also pops when clicking the Start Order button and makes the game freeze for seconds.

22x .../Modules/ReagentOptimization/ReagentOptimization.lua:158: attempt to index field '?' (a nil value)
[string "@CraftSim/Modules/ReagentOptimization/ReagentOptimization.lua"]:158: in function optimizeKnapsack' [string "@CraftSim/Modules/ReagentOptimization/ReagentOptimization.lua"]:470: in function OptimizeReagentAllocation'
[string "@CraftSim/Classes/RecipeData.lua"]:651: in function OptimizeReagents' [string "@CraftSim/Init/Init.lua"]:737: in function TriggerModulesByRecipeType'
[string "@CraftSim/Init/Init.lua"]:85: in function <CraftSim/Init/Init.lua:83>
[string "@CraftSim/Libs/GUTIL/GUTIL.lua"]:605: in function checkCondition' [string "@CraftSim/Libs/GUTIL/GUTIL.lua"]:611: in function WaitFor'
[string "@CraftSim/Init/Init.lua"]:74: in function TriggerModuleUpdate' [string "@CraftSim/Init/Init.lua"]:126: in function <CraftSim/Init/Init.lua:106> [string "=[C]"]: ? [string "=[C]"]: in function Init'
[string "@Blizzard_ProfessionsTemplates/Blizzard_ProfessionsRecipeSchematicForm.lua"]:192: in function <...emplates/Blizzard_ProfessionsRecipeSchematicForm.lua:186>
[string "=[C]"]: in function Show' [string "@Blizzard_Professions/Blizzard_ProfessionsCrafterOrderPage.lua"]:759: in function ViewOrder'
[string "@Blizzard_Professions/Blizzard_ProfessionsCrafterOrderPage.lua"]:64: in function <...Professions/Blizzard_ProfessionsCrafterOrderPage.lua:59>

Locals:
self =

{
UI = {
}
}
ks = {
1 = {
}
0 = {
}
}
BPs = {
1 = 0.573171
2 = 0
3 = -1
4 = -1
0 = -1
}
recipeData = {
isGear = true
reagentData = {
}
specializationDataCached = false
relativeProfitCached = 34
recipeIcon = 4419344
specializationData = {
}
supportsCraftingStats = true
supportsQualities = true
supportsCraftingspeed = true
priceData = {
}
learned = true
maxQuality = 5
recipeInfoCached = false
concentrationCurveData = {
}
isAlchemicalExperimentation = false
recipeInfo = {
}
concentrationCost = 239
baseOperationInfo = {
}
professionStatModifiers = {
}
maxItemAmount = 1
professionStats = {
}
supportsMulticraft = false
expansionID = 10
cooldownData = {
}
subRecipeDepth = 0
isOldWorldRecipe = false
parentRecipeInfo = {
}
orderData = {
}
supportsSpecializations = true
baseProfessionStats = {
}
concentrating = false
isBaseRecraftRecipe = false
crafterData = {
}
isCrafterInfoCached = true
isCooking = false
isSoulbound = true
recipeID = 435376
averageProfitCached = 5948245.048840
buffData = {
}
minItemAmount = 1
numSkillUps = 1
baseItemAmount = 1
isRecraft = false
resultData = {
}
hasQualityReagents = true
isQuestRecipe = false
recipeName = "Forger's Font Inspector"
optimizedSubRecipes = {
}
supportsIngenuity = true
isSimulationModeData = false
subRecipeCostsEnabled = false
professionGearCached = false
hasReagents = true
concentrationData = {
}
isSalvageRecipe = false
isEnchantingRecipe = false
professionGearSet = {
}
supportsResourcefulness = true
professionData = {
}
operationInfoCached = false
categoryID = 1994
}
numMaterials = 1
i = nil
j = -192
k = nil
maxWeight = 454
inf = Infinite
b = {
1 = {
}
0 = {
}
}
c = {
1 = {
}
0 = {
}
}
i = 1
minValue = Infinite
outArr = {
}
outResult = {
}
target = 0
h = 0
tStart = 261
tEnd = 454
lowestj = 0
matString = ""
(for index) = 1
(for limit) = 4
(for step) = 1
h = 1
outAllocation = {
allocations = {
}
}
(for index) = 0
(for limit) = 0
(for step) = -1
i = 0
matAllocations = {
}
(*temporary) = nil
(*temporary) = {
allocations = {
}
}
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = {
1 = {
}
2 = {
}
3 = {
}
}
(*temporary) = {
allocations = 0
itemID = 213221
quality = 3
}
(*temporary) = 213221
(*temporary) = {
itemID = 213221
}
(*temporary) = "attempt to index field '?' (a nil value)"
GUTIL = {
COLORS = {
}
Object = {
}
eventWaitFrame = Frame {
}
Formatter = {
}
}
CraftSim = {
COOLDOWNS = {
}
STATISTICS = {
}
OPTIONAL_REAGENT_DATA = {
}
NEWS = {
}
CraftRecipeData = {
}
DEBUG = {
}
PRICE_DETAILS = {
}
ProfessionGear = {
}
CRAFT_BUFFS = Frame {
}
NodeData = {
}
PRICE_OVERRIDE = {
}
ConcentrationData = {
}
LOCAL_MX = {
}
ENCHANT_RECIPE_DATA = {
}
REAGENT_DATA = {
}
COST_OPTIMIZATION = {
}
EXPLANATIONS = {
}
LibCompress = {
}
TopGearResult = {
}
ReagentData = {
}
LOCAL_DE = {
}
CONCENTRATION_TRACKER = {
}
SUPPORTERS = {
}
LibGraph = {
}
OptionalReagentSlot = {
}
Reagent = {
}
PRICE_APIS = {
}
LOCAL_FR = {
}
SPECIALIZATION_DATA = {
}
PRICE_SOURCE = {
}
UTIL = {
}
LOCAL_ES = {
}
CraftSimObject = {
}
PerkData = {
}
ITEM_COUNT = Frame {
}
TOPGEAR = {
}
PriceData = {
}
OptionalReagent = {
}
CONCENTRATION_CURVE_DATA = {
}
LOCAL_IT = {
}
CONTROL_PANEL = {
}
CraftQueueItem = <