Keep getting this lua error, might be a dupe thread of #4 but my LUA error looks different so unsure.
Been happening since DF launch, posted on the curseforge comments about a month ago. Happens 99% of the time, every single session when playing.

125x TooltipItemIcon/TooltipItemIcon.lua:437: attempt to index upvalue 'options' (a nil value)
[string "@TooltipItemIcon/TooltipItemIcon.lua"]:437: in function <TooltipItemIcon/TooltipItemIcon.lua:435>
[string "=(tail call)"]: ?
[string "=[C]"]: in function securecallfunction' [string "@SharedXML/Tooltip/TooltipDataHandler.lua"]:60: in function <SharedXML/Tooltip/TooltipDataHandler.lua:55> [string "@SharedXML/Tooltip/TooltipDataHandler.lua"]:80: in function <SharedXML/Tooltip/TooltipDataHandler.lua:76> [string "@SharedXML/Tooltip/TooltipDataHandler.lua"]:116: in function <SharedXML/Tooltip/TooltipDataHandler.lua:106> [string "=[C]"]: in function SetAttribute'
[string "@SharedXML/Tooltip/TooltipDataHandler.lua"]:141: in function <SharedXML/Tooltip/TooltipDataHandler.lua:134>
[string "@SharedXML/Tooltip/TooltipDataHandler.lua"]:282: in function <SharedXML/Tooltip/TooltipDataHandler.lua:240>
[string "=[C]"]: in function `securecallfunction'
[string "@SharedXML/Tooltip/TooltipDataHandler.lua"]:237: in function <SharedXML/Tooltip/TooltipDataHandler.lua:236>
[string "=(tail call)"]: ?
[string "@XLoot_Frame/Frame.lua"]:225: in main chunk

Locals:
frame = XLootTooltip {
0 =
SetQuestLogRewardSpell = defined @SharedXML/Tooltip/TooltipDataHandler.lua:444
SetQuestPartyProgress = defined @SharedXML/Tooltip/TooltipDataHandler.lua:444
ProcessLineData = defined @SharedXML/Tooltip/TooltipDataHandler.lua:303
SetPvpTalent = defined @SharedXML/Tooltip/TooltipDataHandler.lua:444
SetRuneforgeResultItem = defined @SharedXML/Tooltip/TooltipDataHandler.lua:444
SetHyperlink = defined @SharedXML/Tooltip/TooltipDataHandler.lua:444
SetUnit = defined @SharedXML/Tooltip/TooltipDataHandler.lua:444
SetAzeriteEssence = defined @SharedXML/Tooltip/TooltipDataHandler.lua:444
SetVoidDepositItem = defined @SharedXML/Tooltip/TooltipDataHandler.lua:444
SetVoidWithdrawalItem = defined @SharedXML/Tooltip/TooltipDataHandler.lua:444
SetInfoBackdropStyle = defined @SharedXML/Tooltip/TooltipDataHandler.lua:338
SetSocketGem = defined @SharedXML/Tooltip/TooltipDataHandler.lua:444
info =

The LUA does mentions XLoot, which is another addon that I use, but this LUA error triggers before XLoot is used.
Unsure why your addon conflicts since I don't get an XLoot lua error. This is an TooltipItemIcon error.

My first guess was that your Saved Variables are corrupted.

However looking at how XLoot might be involved, there is a change that XLoot is doing something strange at load time, before TTII gets properly loaded. Do these errors only happen during load time?

This is not the same error as #4, the line number appears to be a coincidence. Also, unfortunately, I did not get any notification from Curseforge when you posted your comment there :(

Most of the time the error will occur after a reload or login on the char, but idk why.
I don't know how to produce it, it just happens. I use bugsack so I'll hear it ping sometimes and it's this LUA.

Please try the 1.81 download (from Curse) and please let me know if it fixes this issue (it's a bit of a wild guess!)

Fixed I believe? no errors as of playing :) thanks a bunch

Thanks for letting me know :)