While visiting the Alchemy shop in Dalaran (Northrend), I get an error when attempting to learn a recipe from Linzy Blackbolt. That is, if I hover over either a trainable or untrainable alchemy skill I get the following error:
============================================================ (my divider)
Message: Interface\AddOns\GearHelper\GearHelper.lua:481: table index is nil
Time: Sun Mar 13 16:42:42 2022
Count: 23
Stack: Interface\AddOns\GearHelper\GearHelper.lua:481: table index is nil
[string "@interface\AddOns\GearHelper\GearHelper.lua"]:481: in function <Interface\AddOns\GearHelper\GearHelper.lua:375>
[string "=[C]"]: ?
[string "=[C]"]: ?
[string "=[C]"]: in function `SetTrainerService'
[string ":OnEnter"]:3: in function <[string ":OnEnter"]:1>

Locals: self = GameTooltip {
0 =
SetText = defined =[C]:-1
SetPvpTalent = defined =[C]:-1
ItemTooltip = {
}
SetHyperlink = defined =[C]:-1
SetVoidDepositItem = defined =[C]:-1
SetVoidWithdrawalItem = defined =[C]:-1
ARKTTD =

{
}
SetLootCurrency = defined =[C]:-1
SetLootItem = defined =[C]:-1
FadeOut = defined =[C]:-1
SetQuestLogSpecialItem = defined =[C]:-1
SetRecipeReagentItem = defined =[C]:-1
SetBuybackItem = defined =[C]:-1
SetMerchantItem = defined =[C]:-1
SetMerchantCostItem = defined =[C]:-1
BottomOverlay = {
}
SetSpellByID = defined =[C]:-1
NineSlice = {
}
SetCompanionPet = defined =[C]:-1
SetLootRollItem = defined =[C]:-1
SetBagItem = defined =[C]:-1
SetAction = defined =[C]:-1
SetCurrencyByID = defined =[C]:-1
textLeft1Font = "GameTooltipHeaderText"
SetCurrencyToken = defined =[C]:-1
SetGuildBankItem = defined =[C]:-1
SetVoidItem = defined =[C]:-1
SetArtifactPowerByID = defined =[C]:-1
TextRight1 = GameTooltipTextRight1 {
}
ClearLines = defined =[C]:-1
TopOverlay = {
}
Backdrop = GHGameTooltipBackdrop {
}
SetUnitDebuff = defined =[C]:-1
SetItemByID = defined =[C]:-1
hasMoney = 1
SetQuestItem = defined =[C]:-1
numMoneyFrames = 1
waitingForData = false
SetToyByItemID = defined =[C]:-1
comparing = false
SetInboxItem = defined =[C]:-1
layoutType = "TooltipDefaultLayout"
shoppingTooltips = {
}
SetCurrencyTokenByID = defined =[C]:-1
SetInventoryItem = defined =[C]:-1
SetQuestLogItem = defined =[C]:-1
SetBackpackToken = defined =[C]:-1
SetUnitBuff = defined =[C]:-1
SetTalent = defined =[C]:-1
SetTradePlayerItem = defined =[C]:-1
textRight1Font = "GameTooltipHeaderText"
SetSendMailItem = defined =[C]:-1
SetRecipeRankInfo = defined =[C]:-1
SetQuestCurrency = defined =[C]:-1
textLeft2Font = "GameTooltipText"
updateTooltipTimer = 0.103000
TextRight2 = GameTooltipTextRight2 {
}
TextLeft2 = GameTooltipTextLeft2 {
}
SetUnitAura = defined =[C]:-1
textRight2Font = "GameTooltipText"
SetHeirloomByItemID = defined =[C]:-1
SetItemKey = defined =[C]:-1
needsReset = true
TextLeft1 = GameTooltipTextLeft1 {
}
SetTradeTargetItem = defined =[C]:-1
SetQuestLogCurrency = defined =[C]:-1
SetRecipeResultItem = defined =[C]:-1
}
name = nil
itemLink = nil
shouldBeCompared = false
err = "...erface\AddOns\GearHelper\Gear\GH_StatComputation.lua:32: ItemLink is not valid"
linesToAdd = {
}
isItemEquipped = false
(*temporary) = {
}
(*temporary) = {
}
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = "table index is nil"
tooltipProcessed = {
}
ShouldDisplayNotEquippable = defined @interface\AddOns\GearHelper\GearHelper.lua:360
L = {
demande4esES2 = " que acabas de recibir "
demande2 = " if he needs "
DNR = "Do not
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I don't know if the unfinished line at the end is part of the problem or just an artifact of the error system in that there is a limit in the number of characters allowed.

I am a level 60 mage and my WotLK alchemy skill is 25.