I had the below LUA error in these circumstances, not sure which one is relevant but it's gotta be some combination of them because I have these favorites for months and used to do this several times a day and this is the first time this error popped up for Alchemy (seen it many times for other professions but not for Alchemy).

1. Alchemy toon, first recipe in Favorites is Transmute: Meat to Pet (that opens by default)
2. Log in, don't open anything yet
3. Go near Alchemy Lab Bench
4. Open Alchemy page
5. This error popped up:

8x CraftSim/Data/Classes/NodeData.lua:36: attempt to index local 'nodeInfo' (a nil value)
[string "@CraftSim/Data/Classes/NodeData.lua"]:36: in function new' [string "@CraftSim/Libs/classic.lua"]:66: in function NodeData'
[string "@CraftSim/Data/Classes/SpecializationData.lua"]:52: in function parseNode' [string "@CraftSim/Data/Classes/SpecializationData.lua"]:78: in function new'
[string "@CraftSim/Libs/classic.lua"]:66: in function SpecializationData' [string "@CraftSim/Data/Classes/RecipeData.lua"]:107: in function new'
[string "@CraftSim/Libs/classic.lua"]:66: in function RecipeData' [string "@CraftSim/Main/CraftSim.lua"]:505: in function TriggerModulesByRecipeType'
[string "@CraftSim/Main/CraftSim.lua"]:165: in function TriggerModulesErrorSafe' [string "@CraftSim/Main/CraftSim.lua"]:199: in function <CraftSim/Main/CraftSim.lua:183> [string "=[C]"]: ? [string "=[C]"]: in function Init'
...
[string "@Blizzard_Professions/Blizzard_ProfessionsFrame.lua"]:155: in function SetProfessionInfo' [string "@Blizzard_Professions/Blizzard_ProfessionsFrame.lua"]:55: in function <...s/Blizzard_Professions/Blizzard_ProfessionsFrame.lua:53> [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_ProfessionsTemplates/Blizzard_Professions.lua"]:1139: in function set' [string "@FrameXML/FilterDropDown.lua"]:103: in function func'
[string "@SharedXML/UIDropDownMenu.lua"]:1007: in function `UIDropDownMenuButton_OnClick'
[string "*UIDropDownMenuTemplates.xml:136_OnClick"]:1: in function <[string "*UIDropDownMenuTemplates.xml:136_OnClick"]:1>

Locals:
self =

I'm getting a similar error from Blacksmithing:

4x CraftSim/Data/Classes/NodeData.lua:36: attempt to index local 'nodeInfo' (a nil value)
[string "@CraftSim/Data/Classes/NodeData.lua"]:36: in function `new'
[string "@CraftSim/Libs/classic.lua"]:66: in function `NodeData'
[string "@CraftSim/Data/Classes/SpecializationData.lua"]:52: in function `parseNode'
[string "@CraftSim/Data/Classes/SpecializationData.lua"]:78: in function `new'
[string "@CraftSim/Libs/classic.lua"]:66: in function `SpecializationData'
[string "@CraftSim/Data/Classes/RecipeData.lua"]:107: in function `new'
[string "@CraftSim/Libs/classic.lua"]:66: in function `RecipeData'
[string "@CraftSim/Main/CraftSim.lua"]:505: in function `TriggerModulesByRecipeType'
[string "@CraftSim/Main/CraftSim.lua"]:165: in function `TriggerModulesErrorSafe'
[string "@CraftSim/Main/CraftSim.lua"]:199: in function <CraftSim/Main/CraftSim.lua:183>
[string "=[C]"]: ?
[string "=[C]"]: in function `Init'
...
[string "@SharedXML/Scroll/ScrollUtil.lua"]:354: in function `SelectElementDataByPredicate'
[string "@Blizzard_ProfessionsTemplates/Blizzard_ProfessionsRecipeList.lua"]:163: in function `SelectRecipe'
[string "@Blizzard_Professions/Blizzard_ProfessionsCrafting.lua"]:699: in function `Init'
[string "@Blizzard_Professions/Blizzard_ProfessionsCrafting.lua"]:711: in function `Refresh'
[string "@Blizzard_Professions/Blizzard_ProfessionsFrame.lua"]:193: in function `Refresh'
[string "@Blizzard_Professions/Blizzard_ProfessionsFrame.lua"]:158: in function `SetProfessionInfo'
[string "@Blizzard_Professions/Blizzard_ProfessionsFrame.lua"]:66: in function `ProcessOpenRecipeResponse'
[string "@Blizzard_Professions/Blizzard_ProfessionsFrame.lua"]:119: in function <...s/Blizzard_Professions/Blizzard_ProfessionsFrame.lua:59>
[string "=[C]"]: in function `OpenRecipe'
[string "@CraftSim/Main/CraftSim.lua"]:340: in function <CraftSim/Main/CraftSim.lua:334>

Locals:
self = <table> {
 recipeData = <table> {
 }
 nodeRules = <table> {
 }
 nodeID = 40008
 idMapping = <table> {
 }
 professionStats = <table> {
 }
 childNodes = <table> {
 }
}
recipeData = <table> {
 isEnchantingRecipe = false
 isCooking = false
 recipeIcon = 4182964
 supportsCraftingStats = true
 categoryID = 1665
 learned = true
 isRecraft = false
 supportsCraftingspeed = true
 isSalvageRecipe = false
 recipeID = 376493
 supportsInspiration = false
 recipeName = "Amice of the Blue"
 isGear = true
 maxQuality = 5
 supportsMulticraft = false
 recipeType = 1
 supportsQualities = true
 isSimulationModeData = false
 isOldWorldRecipe = false
 supportsResourcefulness = false
 professionData = <table> {
 }
 subtypeID = 1
 numSkillUps = 1
}
nodeRulesData = <table> {
 1 = <table> {
 }
}
parentNode = nil
configID = 0
nodeInfo = nil
(*temporary) = <function> defined =[C]:-1
(*temporary) = 0
(*temporary) = 40008
(*temporary) = "attempt to index local 'nodeInfo' (a nil value)"

Are this errors still occuring as of 8.0+?

Still happening.
Just tried to open something with the filter set to Zandalari Engineering and got this:

1x CraftSim/Data/Classes/NodeData.lua:31: attempt to index local 'nodeInfo' (a nil value)
[string "@CraftSim/Data/Classes/NodeData.lua"]:31: in function new' [string "@CraftSim/Libs/classic.lua"]:66: in function NodeData'
[string "@CraftSim/Data/Classes/SpecializationData.lua"]:49: in function parseNode' [string "@CraftSim/Data/Classes/SpecializationData.lua"]:75: in function new'
[string "@CraftSim/Libs/classic.lua"]:66: in function SpecializationData' [string "@CraftSim/Data/Classes/RecipeData.lua"]:71: in function new'
[string "@CraftSim/Libs/classic.lua"]:66: in function RecipeData' [string "@CraftSim/Main/CraftSim.lua"]:529: in function TriggerModulesByRecipeType'
[string "@CraftSim/Main/CraftSim.lua"]:189: in function TriggerModulesErrorSafe' [string "@CraftSim/Main/CraftSim.lua"]:234: in function <CraftSim/Main/CraftSim.lua:207> [string "=[C]"]: ? [string "=[C]"]: in function Init'
...
[string "@Blizzard_Professions/Blizzard_ProfessionsFrame.lua"]:155: in function SetProfessionInfo' [string "@Blizzard_Professions/Blizzard_ProfessionsFrame.lua"]:55: in function <...s/Blizzard_Professions/Blizzard_ProfessionsFrame.lua:53> [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_ProfessionsTemplates/Blizzard_Professions.lua"]:1139: in function set' [string "@FrameXML/FilterDropDown.lua"]:103: in function func'
[string "@SharedXML/UIDropDownMenu.lua"]:1007: in function `UIDropDownMenuButton_OnClick'
[string "*UIDropDownMenuTemplates.xml:136_OnClick"]:1: in function <[string "*UIDropDownMenuTemplates.xml:136_OnClick"]:1>

Locals:
self =