Running Software (issues missing this information will be deleted):

• Addon version:8.21
• Server patch: [e.g. Build 8.0.1.27178]

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Describe the bug
A clear and concise description of what the bug is.
Lua Error on sale of items
To Reproduce
Steps to reproduce the behaviour:

1. Go to Vendor
2. Click on item to sell
3. See error

Expected behaviour
A clear and concise description of what you expected to happen.

Screenshots
If applicable, add screenshots to help explain your problem.

Error Logs
Type /console scriptErrors 1 in the chat and reload the game. If an error window appears, write here the first message (labelled 1/Many) that appeared.
Date: 2019-12-26 14:57:10
ID: 1
Error occured in: Global
Count: 1
Message: ..\AddOns\Scrap\addons\merchant\learning.lua line 41:
attempt to call method 'CheckFilters' (a nil value)
Debug:
[C]: CheckFilters()
Scrap\addons\merchant\learning.lua:41: OnItemSold()
Scrap\addons\merchant\learning.lua:26:
Scrap\addons\merchant\learning.lua:24
[C]: UseContainerItem()
..\FrameXML\ContainerFrame.lua:1254: ContainerFrameItemButton_OnClick()
[string ":OnClick"]:12:
[string ":OnClick"]:1
[C]: ?
Locals:

AddOns:
MoncaiCompare, v7.2.0
Swatter, v8.2.6377 (SwimmingSeadragon)
ACP, v3.5.6
AdvancedInterfaceOptions, v1.3.3
Atlas, vv1.45.01.11302
AtlasClassicWoW, vv1.45.00.11302.05
AtlasLootClassic, vv1.4.4
AtlasLootClassicData, vv1.4.4
AtlasLootClassicDungeonsAndRaids, vv1.4.4
AtlasQuest, v4.11.58
AucAdvanced, v8.2.6430 (SwimmingSeadragon)
AucFilterBasic, v8.2.6364 (SwimmingSeadragon)
AucScanData, v8.2.6365 (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)
Auctionator, v8.1.0
AutoLootPlus, v2.0.0-11302
BadBoy, vv1-classic
BagBrother, v
Bagnon, v8.2.27
BagnonScrap, v8.2.1
BankStack, vv11302.0
Bartender4, v4.8.9
BeanCounter, v8.2.6434 (SwimmingSeadragon)
BetterVendorPrice, vv1.11.00
BootyBayGazette, v6.1.20191223
ClassicSpellActivations, v
D4KiRMissingPower, v3.1 Release
DBMCore, v1.13.25
DBMDefaultSkin, v
DBMStatusBarTimers, v
DejaClassicStats, v1303r001
Details, v
DetailsStreamer, v
DetailsTinyThreat, v
Diminish, vv2.2.5
DiminishOptions, v
EasyMail, v4.3
FastGuildInvite, v59
GatherMate2, v1.45.5
GTFO, v4.51
Guidelime, v1.040
GuidelimeSage, v1.0
HealBot, v1.13.3.1
HealBotData, v1.13.3.0
HealBoten, v1.13.3.0
HealBotOptions, v1.13.3.0
HealBotTips, v1.13.3.1
honorspy, v1.6.7
InFlightLoad, v1.13.003
Informant, v8.2.6374 (SwimmingSeadragon)
ItemRack, v
KillTrack, vv1.13.0
LeatrixMaps, v1.13.41
LeatrixPlus, v1.13.42
LetMeCast, v1.3
LibSharedMedia30, v3.0-113
lsToasts, v11302.02
Mapster, v1.8.5
Masque, v8.2.8-Classic
MasqueRaeli, vr19-release
MBB, v4.0
MikScrollingBattleText, v5.7.149
MissingTradeSkillsList, v1.13.28
Misspelled, v1.7.4
MonkeyClock, vv3.2.0
MonkeySpeed, vv3.4.0
NeatPlates, v1.13.3.2
NeatPlatesAlvara, v5a
NeatPlatesBlizzardPlates, v1.5
NeatPlatesClassicPlates, v
NeatPlatesGraphite, v
NeatPlatesGrey, v
NeatPlatesNeon, v
NeatPlatesQuatre, v
NeatPlatesRenaitre, vv7.0.3
NeatPlatesRoth, v
NeatPlatesSimple, v7.3.0
NeatPlatesSlimHorizontal, v2.2
NeatPlatesSlimVertical, v2.2
NeatPlatesHub, v
NeatPlatesWidgets, v
OmniBar, vv10.7
OmniCC, v8.3.1
Peggle, v2.2.6
Prat30, v3.7.45
Prat30Libraries, v
Quartz, v3.5-classic-5
QuartzProcs, v3.6
QuestFrameFixer, v1.1.1
QuestIconDesaturation, v3.1
Questie, v5.4.1
RealMobHealth, v2.17
Scrap, v8.2.1
ScrapBroker, v8.2.1
ScrapMerchant, v
ShadowedUnitFrames, vv4.2.2-Classic
SilverDragon, vv11302.0
SilverDragonClassic, vv11302.0
SimpleMap, v1.2.1
SlideBar, v8.2.6375 (SwimmingSeadragon)
SmartQuest, v1.18
Spy, v1.0.20
Stubby, v8.2.6376 (SwimmingSeadragon)
TalentSequence, v2.0
TipTac, v19.03.31
TipTacItemRef, v19.03.31
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
TitanClassicLocation, v1.1.5.11303
TitanClassicLootType, v1.1.5.11303
TitanClassicPerformance, v1.1.5.11303
TitanClassicRegen, v1.1.5.11303
TitanClassicRepair, v1.1.5.11303
TitanClassicVolume, v1.1.5.11303
TitanClassicXP, v1.1.5.11303
TitanSocial, v1.13.3
TomTom, vv11303-1.0.9
TotalQuestXP, v1.7
TradeSkillMaster, vv4.8.24
TradeSkillMasterAppHelper, vv4.0.6
TrinketMenu, v7.3.2
TwitchEmotes, vv2
VendorPrice, v1.3.0
WeakAuras, v2.15.5
WeakAurasCompanion, v1.0.0
WeaponSwingTimer, v4.1.0
WhatsTraining, v1.8.7
WIM, v3.8.4
BlizRuntimeLib_enUS v1.13.3.11303
(ck=e7c)

Additional context
Add any other context about the problem here.

Yup, yup. Fixed and releasing new version