When mousing over items in chat I SOMETIMES get the following error:

4x KiwiItemInfo\Tooltip.lua:834: attempt to concatenate a nil value
KiwiItemInfo\Tooltip.lua:834: in function ShowEffectiveStats' KiwiItemInfo\KiwiItemInfo-v2.3.5-beta_002.lua:224: in function <KiwiItemInfo\KiwiItemInfo.lua:221> [C]: ? [C]: ? [C]: ? [C]: ? [C]: in function SetCompareItem'
FrameXML\GameTooltip.lua:716: in function <FrameXML\GameTooltip.lua:713>
(tail call): ?
FrameXML\GameTooltip.lua:545: in function <FrameXML\GameTooltip.lua:543>
[C]: ?
[C]: ?
...
[C]: ?
[C]: ?
[C]: ?
[C]: ?
[C]: ?
[C]: ?
MobInfo2-Classic\MI2_Events.lua:677: in function <MobInfo2-Classic\MI2_Events.lua:674>
[C]: ?
...eBartender4\libs\AceHook-3.0\AceHook-3.0-8.lua:95: in function <...eBartender4\libs\AceHook-3.0\AceHook-3.0.lua:87>
[C]: ?

Locals:
tooltip = ShoppingTooltip1 {
0 =
SetCompareItem = defined =[C]:-1
updateTooltip = 0.200000
hasMoney = 1
PawnIconFrame = {
}
SetUnitAura = defined =[C]:-1
TopOverlay = {
}
shownMoneyFrames = 1
SetHyperlink = defined =[C]:-1
needsReset = true
BottomOverlay = {
}
numMoneyFrames = 1
SetUnitDebuff = defined =[C]:-1
SetUnitBuff = defined =[C]:-1
}
selection = {
0 =
messageInfo =

{
}
}
name = nil
_ = "Rogue"
_ = "ROGUE"
classID = 4
armor = 599
ch_agi = 84
_ = 84
ch_agi_pos = 26
ch_agi_neg = 0
ch_stm = 55
_ = 55
ch_stm_pos = 19
ch_stm_neg = 0
ch_str = 36
_ = 36
ch_str_pos = 2
ch_str_neg = 0
ch_int = 29
_ = 29
ch_int_pos = 1
ch_int_neg = 0
ch_spt = 37
_ = 37
ch_spt_pos = 8
ch_spt_neg = 0
agility_ap_melee = 0
agility_ap_range = 0
agility_crit = 0
agility_dodge = 0
agility_catform_ap_melee = 0
agility_armor = 0
eff_agility_armor = 0
stamina_health = 0
eff_stamina_health = 0
strength_ap_melee = 0
strength_block = 0
intellect_mana = 0
intellect_crit = 0
spirit_hpt = 0
spirit_mpt = 0
arcane_resist_p = 0
fire_resist_p = 2.857143
frost_resist_p = 0
nature_resist_p = 0
shadow_resist_p = 0
eff_arcane_resist_p = 0
eff_fire_resist_p = Infinite
eff_frost_resist_p = Infinite
eff_nature_resist_p = Infinite
eff_shadow_resist_p = Infinite
eff_agility_ap_melee = 0
eff_agility_ap_range = 0
eff_agility_crit = 0
eff_agility_dodge = 0
eff_agility_catform_ap_melee = 0
eff_strength_ap_melee = 0
eff_strength_block = 0
eff_intellect_mana = 0
eff_intellect_crit = 0
eff_spirit_hpt = 0
eff_spirit_mpt = 0
eff_armor = 60.100167
eff_agi = 0
eff_stm = 0
eff_str = 0
eff_int = 0
eff_spt = 0
queue = {
1 = {
}
2 = {
}
3 = {
}
4 = {
}
5 = {
}
6 = {
}
}
dirty = false
send_line = defined @KiwiItemInfo\Tooltip.lua:692
blank_if_dirty = defined @KiwiItemInfo\Tooltip.lua:696
(*temporary) = defined @KiwiItemInfo\Tooltip.lua:692
(*temporary) = "Fire Resist: "
(*temporary) = defined =[C]:-1
(*temporary) = "|cFFEFEF00%s|r"
(*temporary) = nil
(*temporary) = "%"
(*temporary) = "%d+%.?%d?%d?"
(*temporary) = nil
(*temporary) = {
1 = "Armor: |cFFEFEF0060.10%|r"
2 = 1
3 = 1
4 = 1
5 = false
}
(*temporary) = "Armor: |cFFEFEF0060.10%|r"
(*temporary) = "attempt to concatenate a nil value"
att1 = {
dps = 0
max_dmg = 0
min_dmg = 0
}
basic1 = {
Intellect = 0
Agility = 0
Stamina = 0
Strength = 0
Spirit = 0
}
resist1 = {
Shadow_Resist = 0
Arcane_Resist = 0
Nature_Resist = 0
Frost_Resist = 0
Fire_Resist = 12
}
def1 = {
Armor = 360
Block = 0
Durability = 0
}
L = {
VUI_SHOW_ILVL = "Show iLvl:"
TOOLTIP_STACK = "Stack:"
VUI_DEFAULT_ILVL_COLOR = "Default iLvl Coloration:"
VUI_ITEM_ILVL = "Show iLvl On Items:"
COMMAND_RESET = "Resetting KiwiItemInfo..."
KIWIII_RESET = "reset"
COMMAND_SEARCH_ONE_HANDED = "One-Handed "
COMMAND_SEARCH_TWO_HANDED = "Two-Handed "
TOOLTIP_EX_RES_ARCANE = "Arcane Resist: "
TOOLTIP_IC_ARCANE = "Arcane Resistance"
COMMAND_SET_ERROR_STRING = "Kiwi expects a string value (words). Sorry."
TOOLTIP_EX_RES_SHADOW = "Shadow Resist: "
COMMAND_SEARCH_ARG_LEN = "Kiwi Item Info: Invalid argument length"
COMMAND_HELP3 = "Usage: /kiwiii [reload] [reset] [vars] [aci]"
COMMAND_SEARCH_2H = "Two"
TOOLTIP_EX_AGI_AR = "Agility Armor: "
TOOLTIP_ITEM_COMPARE = "Kiwi says equipping will do this:"
TOOLTIP_CMP_DURABILITY = "[DURABILITY]+%s%d+%s/%s%d+"
TOOLTIP_CMP_DAMAGE = "%d+%s%-%s%d+%s[DAMAGE]+"
COMMAND_SET_ERROR_VAR = "Kiwi doesn't have such a variable. Sorry."
COMMAND_SET_ERROR_NUMBER = "Kiwi expects a number value. Sorry."
KIWIII_HELP = "help"
TOOLTIP_EX_AGI_M_CAT_AP = "Agility Catform AP: "
COMMAND_HELP19 = " * |cFFBBBBBBitemname|r -- search for items"
KIWIII_SEARCH = "search"
TOOLTIP_EX_STR_BLOCK = "Strength Block: "
KIWIII_SET = "set"
TOOLTIP_CMP_SHADOW = "[+-]%d+%s[SHADOW RESISTANCE

I really appreciate your work and wish I could help resolve issues, at my age it is hard to learn new tricks...

There is no certain item that triggers the error, just passing over items in chat.

Date: 2020-01-13 00:58:57
ID: -1
Error occured in: Global
Count: ∞
Message: ..\AddOns\KiwiItemInfo\Tooltip.lua line 775:
attempt to concatenate a nil value
Debug:
KiwiItemInfo\Tooltip.lua:775: ShowEffectiveStats()
KiwiItemInfo\KiwiItemInfo.lua:224:
KiwiItemInfo\KiwiItemInfo.lua:221
[C]: ?
[C]: ?
[C]: ?
[C]: ?
[C]: SetCompareItem()
..\FrameXML\GameTooltip.lua:716:
..\FrameXML\GameTooltip.lua:713
(tail call): ?
..\FrameXML\GameTooltip.lua:545:
..\FrameXML\GameTooltip.lua:543
[C]: ?
[C]: ?
[C]: ?
[C]: ?
[C]: ?
[C]: ?
[C]: ?
[C]: ?
[C]: ?
[C]: ?
[C]: ?
[C]: ?
[C]: ?
MobInfo2-Classic\MI2_Events.lua:677:
MobInfo2-Classic\MI2_Events.lua:674
[C]: ?
...e\AddOns\Bartender4\libs\AceHook-3.0\AceHook-3.0.lua:95:
...e\AddOns\Bartender4\libs\AceHook-3.0\AceHook-3.0.lua:87
[C]: ?
[C]: ?
[C]: ?
[C]: SetLootRollItem()
[string ":OnUpdate"]:3:
[string ":OnUpdate"]:1
Locals:
tooltip = ShoppingTooltip1 {
0 =
SetCompareItem = defined =[C]:-1
numMoneyFrames = 1
updateTooltip = 0.200000
PawnIconFrame = {
}
SetUnitAura = defined =[C]:-1
TopOverlay = {
}
shownMoneyFrames = 1
SetHyperlink = defined =[C]:-1
SetUnitDebuff = defined =[C]:-1
BottomOverlay = {
}
needsReset = true
SetUnitBuff = defined =[C]:-1
hasMoney = 1
}
selection = {
0 =
hasItem = 1
Icon = {
}
Count = {
}
}
name = nil
_ = "Rogue"
_ = "ROGUE"
classID = 4
armor = 617
ch_agi = 93
_ = 93
ch_agi_pos = 33
ch_agi_neg = 0
ch_stm = 80
_ = 80
ch_stm_pos = 43
ch_stm_neg = 0
ch_str = 35
_ = 35
ch_str_pos = 0
ch_str_neg = 0
ch_int = 29
_ = 29
ch_int_pos = 1
ch_int_neg = 0
ch_spt = 40
_ = 40
ch_spt_pos = 10
ch_spt_neg = 0
agility_ap_melee = 0
agility_ap_range = 0
agility_crit = 0
agility_dodge = 0
agility_catform_ap_melee = 0
agility_armor = 0
eff_agility_armor = 0
stamina_health = 70
eff_stamina_health = 16.279070
strength_ap_melee = 3
strength_block = 0
intellect_mana = 0
intellect_crit = 0
spirit_hpt = 0
spirit_mpt = 0
arcane_resist_p = 0
fire_resist_p = 0
frost_resist_p = 0
nature_resist_p = 0
shadow_resist_p = 0
eff_arcane_resist_p = 0
eff_fire_resist_p = Infinite
eff_frost_resist_p = Infinite
eff_nature_resist_p = Infinite
eff_shadow_resist_p = Infinite
eff_agility_ap_melee = 0
eff_agility_ap_range = 0
eff_agility_crit = 0
eff_agility_dodge = 0
eff_agility_catform_ap_melee = 0
eff_strength_ap_melee = Infinite
eff_strength_block = 0
eff_intellect_mana = 0
eff_intellect_crit = 0
eff_spirit_hpt = 0
eff_spirit_mpt = 0
eff_armor = 14.424635
eff_agi = 0
eff_stm = 16.279070
eff_str = Infinite
eff_int = 0
eff_spt = 0
queue =

{
1 = {
}
2 = {
}
3 = {
}
4 = {
}
5 = {
}
6 = {
}
7 = {
}
}
dirty = true
send_line = defined @interface\AddOns\KiwiItemInfo\Tooltip.lua:692
blank_if_dirty = defined @interface\AddOns\KiwiItemInfo\Tooltip.lua:696
(*temporary) = defined @interface\AddOns\KiwiItemInfo\Tooltip.lua:692
(*temporary) = "Strength"
(*temporary) = ": "
(*temporary) = defined =[C]:-1
(*temporary) = "%s"
(*temporary) = nil
(*temporary) = "%"
(*temporary) = "%d+%.?%d?%d?"
(*temporary) = nil
(*temporary) = "Stamina: 16.27%"
(*temporary) = "attempt to concatenate a nil value"
att1 = {
dps = 0
max_dmg = 0
min_dmg = 0
}
basic1 = {
Intellect = 0
Agility = 0
Stamina = 7
Strength = 3
Spirit = 0
}
resist1 = {
Shadow_Resist = 0
Arcane_Resist = 0
Nature_Resist = 0
Frost_Resist = 0
Fire_Resist = 0
}
def1 = {
Armor = 89
Block = 0
Durability = 0
}
L = {
VUI_SHOW_ILVL = "Show iLvl:"
TOOLTIP_STACK = "Stack:"
VUI_DEFAULT_ILVL_COLOR = "Default iLvl Coloration:"
VUI_ITEM_ILVL = "Show iLvl On Items:"
COMMAND_RESET = "Resetting KiwiItemInfo..."
KIWIII_RESET = "reset"
COMMAND_SEARCH_ONE_HANDED = "One-Handed "
COMMAND_SEARCH_TWO_HANDED = "Two-Handed "
TOOLTIP_EX_RES_ARCANE = "Arcane Resist: "
TOOLTIP_IC_ARCANE = "Arcane Resistance"
COMMAND_SET_ERROR_STRING = "Kiwi expects a string value (words). Sorry."
TOOLTIP_EX_RES_SHADOW = "Shadow Resist: "
COMMAND_SEARCH_ARG_LEN = "Kiwi Item Info: Invalid argument length"
COMMAND_HELP3 = "Usage: /kiwiii [reload] [reset] [vars] [aci]"
COMMAND_SEARCH_2H = "Two"
TOOLTIP_EX_AGI_AR = "Agility Armor: "
TOOLTIP_ITEM_COMPARE = "Kiwi says equipping will do this:"
TOOLTIP_CMP_DURABILITY = "[DURABILITY]+%s%d+%s/%s%d+"
TOOLTIP_CMP_DAMAGE = "%d+%s%-%s%d+%s[DAMAGE]+"
COMMAND_SET_ERROR_VAR = "Kiwi doesn't have such a variable. Sorry."
COMMAND_SET_ERROR_NUMBER = "Kiwi expects a number value. Sorry."
KIWIII_HELP = "help"
TOOLTIP_EX_AGI_M_CAT_AP = "Agility Catform AP: "
COMMAND_HELP19 = " * itemname -- search for items"
KIWIII_SEARCH = "search"
TOOLTIP_EX_STR_BLOCK = "Strength Block: "
KIWIII_SET = "set"
TOOLTIP_CMP_SHADOW = "[+-]%d+%s[SHADOW RESISTANCE]+"
AddOns:
Swatter, v8.1.6241 (SwimmingSeadragon)
ACP, v3.5.6
AlreadyKnown, v1.22
AraBrokerGuildFriends, vr81
AraBrokerReputations, vr34
Armory, vv1.6.2
Atlas, vv1.46.04.11303.01
AtlasClassicWoW, vv1.45.01.11303.05
AtlasTransportation, vv1.46.02.11303.00
AtlasLootClassic, vv1.4.4
AtlasLootClassicData, vv1.4.4
AtlasLootClassicDungeonsAndRaids, vv1.4.4
AtlasQuest, v4.11.59
ATTClassic, v0.1.3
Auctionator, v8.1.0
AutoProfit, v1.13.2
BagBrother, v
Bagnon, v8.2.29
BagnonArmory, v1.0.5
Bartender4, v4.8.9
BrokerClassicTracking, v1.1.1
CharacterStatsClassic, v3.1
ClassicTooltipItemLevel, v1.0.0
CTBuffMod, v8.2.5.5
CTCore, v8.2.5.9
CTLibrary, v8.2.5.9
CTMailMod, v8.2.5.9
DBMCore, v1.13.29
DBMDefaultSkin, v
DBMPartyClassic, v
DBMStatusBarTimers, v
DefsToolbox, v80205.10
DispellAlert, v8.0.9c
GatherMate2, v1.45.5
GSE, v2.4.25
GSEGUI, v2.4.25
GSELDB, v2.4.25
GTFO, v4.51
HandyNotes, vv1.5.9-1-g81432ff
HandyNotesDungeonLocationsClassic, v1.03
HandyNotesNPCsClassic, v1.21
HandyNotesWorldMapButton, v11302.02-Classic
InFlightLoad, v1.13.004
ItemAutocomplete, v1.0.5
ItemTooltipProfessionIcons, v1.1.5
KiwiItemInfo, vv2.3.5-beta_002
LeatrixMaps, v1.13.43
LeatrixPlus, v1.13.44
LibStub, v
LibTouristClassic10, v
LightHeaded, vv11302-1.0.0
lsToasts, v11302.02
Misspelled, v1.7.4
MobInfo2Classic, v11302.04
Molinari, v80200.64-Release
MonkeySpeed, vv3.4.0
OmniCC, v8.3.1
Pawn, v2.3.15
QuestAnnounce, v8.0.2.1
QuestCompletist, v109.25
Quester, v1.13.2.1
QuestFrameFixer, v1.1.1
Questie, v5.5.1
RealMobHealth, v2.18
RecipeRadarClassic, v1.0.0.23
Recount, vv1.13.3a
SilverDragon, vv11302.0
SilverDragonClassic, vv11302.0
SimpleDing, vv1.1.1
SimpleItemLevel, v1
SkilletClassic, vr140
SpeedyAutoLoot, v2.0.25
SpellbookAbridged, v2.6.2
TFTB, v1.10
TidyMinimapClassic, v1.0
TipTac, v19.03.31
TipTacItemRef, v19.03.31
TitanAttributesMulti, v1.1
TitanClassic, v1.1.5.11303
TitanClassicAmmo, v1.1.5.11303
TitanClassicBag, v1.1.5.11303
TitanClassicClock, v1.1.5.11303
TitanClassicGold, v1.1.5.11303
TitanClassicItemDed, v1.0.0.3
TitanClassicLocation, v1.1.5.11303
TitanClassicLootType, v1.1.5.11303
TitanClassicPerformance, v1.1.5.11303
TitanClassicRepair, v1.1.5.11303
TitanClassicRestPlus, v1.0.0.1
TitanProfessionsMulti, v1.3
TomTom, vv11303-1.0.9
UsedInRecipe, v1.0.3
WhatsTraining, v1.8.7
WhereToGatherClassic, v1.0
WideQuestLog, v
ZoneInfoClassic, v1.0
ZPerl, v5.8.9
ZPerlArcaneBar, v
ZPerlParty, v
ZPerlPartyPet, v
ZPerlPlayer, v
ZPerlPlayerBuffs, v
ZPerlPlayerPet, v
ZPerlTarget, v
ZPerlTargetTarget, v
BlizRuntimeLib_enUS v1.13.3.11303
(ck=ab1)