It mentions TSM but I do not use the TSM crafting panel so it has nothing to do with that. It seems to happen most frequently when browsing for crafting orders at my crafting table.

5x CraftSim/DataExport.lua:456: bad argument #1 to 'pairs' (table expected, got nil)
[string "=[C]"]: in function `pairs'
[string "@CraftSim/DataExport.lua"]:456: in function `GetProfessionGearStatsByLink'
[string "@CraftSim/DataExport.lua"]:554: in function `GetEquippedProfessionGear'
[string "@CraftSim/GearSim.lua"]:109: in function `GetProfessionGearCombinations'
[string "@CraftSim/GearSim.lua"]:369: in function `SimulateBestProfessionGearCombination'
[string "@CraftSim/CraftSim.lua"]:358: in function `TriggerModulesByRecipeType'
[string "@CraftSim/CraftSim.lua"]:87: in function <CraftSim/CraftSim.lua:83>
[string "=[C]"]: in function `Init'
[string "@Blizzard_ProfessionsTemplates/Blizzard_ProfessionsRecipeSchematicForm.lua"]:188: in function <...emplates/Blizzard_ProfessionsRecipeSchematicForm.lua:182>
[string "=[C]"]: in function `Show'
[string "@FrameXML/UIParent.lua"]:2890: in function `SetUIPanel'
[string "@FrameXML/UIParent.lua"]:2733: in function `ShowUIPanel'
...
[string "@TradeSkillMaster/LibTSM/Util/Event.lua"]:132: in function `ProcessEvent'
[string "@TradeSkillMaster/LibTSM/Util/Event.lua"]:150: in function <TradeSkillMaster/LibTSM/Util/Event.lua:141>
[string "=[C]"]: ?
[string "=[C]"]: in function `UseAction'
[string "@FrameXML/SecureTemplates.lua"]:364: in function `handler'
[string "@FrameXML/SecureTemplates.lua"]:690: in function <FrameXML/SecureTemplates.lua:672>
[string "@FrameXML/SecureTemplates.lua"]:704: in function <FrameXML/SecureTemplates.lua:697>
[string "@FrameXML/SecureTemplates.lua"]:746: in function `SecureActionButton_OnClick'
[string "@FrameXML/ActionButton.lua"]:1175: in function <FrameXML/ActionButton.lua:1145>
[string "=[C]"]: ?

Locals:
(*temporary) = nil
(*temporary) = "table expected, got nil"
 = <function> defined =[C]:-1

also have simular error

47x CraftSim/DataExport.lua:456: bad argument #1 to 'pairs' (table expected, got nil)
[string "=[C]"]: in function pairs' [string "@CraftSim/DataExport.lua"]:456: in function GetProfessionGearStatsByLink'
[string "@CraftSim/DataExport.lua"]:579: in function GetProfessionGearFromInventory' [string "@CraftSim/GearSim.lua"]:110: in function GetProfessionGearCombinations'
[string "@CraftSim/GearSim.lua"]:369: in function SimulateBestProfessionGearCombination' [string "@CraftSim/CraftSim.lua"]:358: in function TriggerModulesByRecipeType'
[string "@CraftSim/CraftSim.lua"]:87: in function <CraftSim/CraftSim.lua:83>
[string "=[C]"]: in function Init' [string "@Blizzard_Professions/Blizzard_ProfessionsCrafting.lua"]:273: in function SelectRecipe'
[string "@Blizzard_Professions/Blizzard_ProfessionsCrafting.lua"]:262: in function <...lizzard_Professions/Blizzard_ProfessionsCrafting.lua:253>
[string "=[C]"]: ?
[string "@SharedXML/CallbackRegistry.lua"]:143: in function <SharedXML/CallbackRegistry.lua:142>
...
[string "@SharedXML/Scroll/ScrollUtil.lua"]:322: in function SelectElementDataByPredicate' [string "@Blizzard_ProfessionsTemplates/Blizzard_ProfessionsRecipeList.lua"]:162: in function SelectRecipe'
[string "@Blizzard_Professions/Blizzard_ProfessionsCrafting.lua"]:692: in function Init' [string "@Blizzard_Professions/Blizzard_ProfessionsCrafting.lua"]:242: in function <...lizzard_Professions/Blizzard_ProfessionsCrafting.lua:241> [string "=[C]"]: ? [string "@SharedXML/CallbackRegistry.lua"]:143: in function <SharedXML/CallbackRegistry.lua:142> [string "=[C]"]: ? [string "@SharedXML/CallbackRegistry.lua"]:146: in function TriggerEvent'
[string "@Blizzard_Professions/Blizzard_ProfessionsFrame.lua"]:133: in function `SetProfessionInfo'
[string "@Blizzard_Professions/Blizzard_ProfessionsFrame.lua"]:88: in function <...s/Blizzard_Professions/Blizzard_ProfessionsFrame.lua:59>

Locals:
(*temporary) = nil
(*temporary) = "table expected, got nil"
= defined =[C]:-1

Should be fixed