Question 5.10.1. I logged into the IF AH and got this error. Looks like a timer assuming a variable that hasn't yet been initialized. Function is _QuestieTracker:StartFadeTicker() and variable is _QuestieTracker.highestIndex.

Message: ...ce\AddOns\Questie\Modules\Tracker\QuestieTracker.lua line 791:
'for' limit must be a number
Debug:
[C]: ?
...ce\AddOns\Questie\Modules\Tracker\QuestieTracker.lua:791:
...ce\AddOns\Questie\Modules\Tracker\QuestieTracker.lua:783
..\SharedXML\C_TimerAugment.lua:16:
..\SharedXML\C_TimerAugment.lua:14

Release of v6.0.0 is coming very soon. Keep an eye on it

Damn I thought I fixed that with the latest release. Thanks for the report I'll have to inspect it closely.

This is caused by some race condition which is not easy to debug.

It seems to be specific to my paladin/smith/miner, and I've only seen it in Ironforge.

I'd suggest adding a nil check on the for limit in case the background code hasn't initialized it yet.

I have just seen this. Warlock in Thunder Bluff v5.10.3 including my error information in case it helps narrow things down.
`Date: 2020-05-13 22:24:22
ID: 1
Error occured in: Global
Count: 1
Message: ...ce\AddOns\Questie\Modules\Tracker\QuestieTracker.lua line 791:
'for' limit must be a number
Debug:
[C]: ?
...ce\AddOns\Questie\Modules\Tracker\QuestieTracker.lua:791:
...ce\AddOns\Questie\Modules\Tracker\QuestieTracker.lua:783
..\SharedXML\C_TimerAugment.lua:16:
..\SharedXML\C_TimerAugment.lua:14
Locals:

AddOns:
Swatter, v8.2.6377 (SwimmingSeadragon)
AucAdvanced, v8.2.6430 (SwimmingSeadragon)
AucFilterBasic, v8.2.6364 (SwimmingSeadragon)
AucStatHistogram, v8.2.6366 (SwimmingSeadragon)
AucStatiLevel, v8.2.6370 (SwimmingSeadragon)
AucStatPurchased, v8.2.6367 (SwimmingSeadragon)
AucStatSimple, v8.2.6399 (SwimmingSeadragon)
AucStatStdDev, v8.2.6369 (SwimmingSeadragon)
AucUtilFixAH, v8.2.6371 (SwimmingSeadragon)
AutoBarClassic, v1.13.3.03
auxaddon, v1.0.0
Bagnon, v8.3.5
BeanCounter, v8.2.6434 (SwimmingSeadragon)
Carbonite, v@project-version@
CarboniteNotes, v@project-version@
CarboniteQuests, v@project-version@
CarboniteSocial, v@project-version@
CarboniteWarehouse, v@project-version@
Details, v
DetailsStreamer, v
DetailsTinyThreat, v
Enchantrix, v8.2.6428 (SwimmingSeadragon)
EnchantrixBarker, v8.2.6469 (SwimmingSeadragon)
GatherMate2, v1.45.5
Informant, v8.2.6374 (SwimmingSeadragon)
Questie, v5.10.3
SlideBar, v8.2.6375 (SwimmingSeadragon)
Stubby, v8.2.6376 (SwimmingSeadragon)
TomCats, v0.0.2
TradeSkillMaster, vv4.9.35
TradeSkillMasterAppHelper, vv4.0.8
BlizRuntimeLib_enUS v1.13.4.11304
(ck=48a)

`

I suspect the OnEnter handler is being invoked if the mouse pointer happens to be over the tracker display when you create it, but before you're done initializing all the data. So you should set a flag at the end of your construction code to check in the fade-in/fade-out code to see if there's anything ready to be animated.

@SpareSimian That might be a good hint. I didn't have any time yet to investigate but will start there once I have time.

Thanks everyone for your help and patient towards this.

Message: ...ce\AddOns\Questie\Modules\Tracker\QuestieTracker.lua:791: 'for' limit must be a number
Time: Thu May 28 19:13:13 2020
Count: 1
Stack: ...ce\AddOns\Questie\Modules\Tracker\QuestieTracker.lua:791: 'for' limit must be a number
...ce\AddOns\Questie\Modules\Tracker\QuestieTracker.lua:791: in function <...ce\AddOns\Questie\Modules\Tracker\QuestieTracker.lua:783>
Interface\SharedXML\C_TimerAugment.lua:16: in function <Interface\SharedXML\C_TimerAugment.lua:14>

Locals: (for index) = 1
(for limit) = nil
(for step) = 1
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = "'for' limit must be a number"
_QuestieTracker =

Just had this error as well. I was not able to reproduce it after /reload or relog.

...ce\AddOns\Questie\Modules\Tracker\QuestieTracker.lua:791: 'for' limit must be a number
...ce\AddOns\Questie\Modules\Tracker\QuestieTracker.lua:791: in function <...ce\AddOns\Questie\Modules\Tracker\QuestieTracker.lua:783>
Interface\SharedXML\C_TimerAugment.lua:16: in function <Interface\SharedXML\C_TimerAugment.lua:14>

Locals: (for index) = 1
(for limit) = nil
(for step) = 1
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = "'for' limit must be a number"

This will be fixed with the upcoming v6.0.0 release. The tracker got some really good reword seen in #1917