Brief Description of Bug

I noticed this issue started happening after the fix for the other issue I raised under ticket #830.
After posting an item in the Selling tab, if I switch to the Sell tab I get 4 errors.
Also, I noticed that the item I just posted in the Selling tab is appearing in the Sell tab - even though I no longer have the item in my inventory as I already posted it using the Selling tab, it is trying to list it again in the Sell tab. So I think that the last item I posted in the Selling tab is not being cleared properly in the game's memory/cache and the game thinks I'm trying to post it still when I switch to the Sell tab...

Steps to Reproduce

Post an item in the Selling tab, then switch to the Sell tab.

Loaded Addons

Accountant 8.0
Auctionator
BadBoy
Battle Pet BreedID
Postal
Rematch
SavedInstances
The Undermine Journal
ElvUI
ElvUI OptionsUI

Back Trace (LUA Error Output)

Error 1:
Message: bad argument #1 to '?' (Usage: local depositCost = C_AuctionHouse.CalculateItemDeposit(item, duration, quantity))
Time: Thu Sep 17 10:38:47 2020
Count: 1
Stack: bad argument #1 to '?' (Usage: local depositCost = C_AuctionHouse.CalculateItemDeposit(item, duration, quantity))
[string "=[C]"]: ?
[string "=[C]"]: in function CalculateItemDeposit' [string "@Interface\AddOns\Blizzard_AuctionHouseUI\Blizzard_AuctionHouseItemSellFrame.lua"]:303: in function GetDepositAmount'
[string "@interface\AddOns\Blizzard_AuctionHouseUI\Blizzard_AuctionHouseSellFrame.lua"]:505: in function UpdateDeposit' [string "@Interface\AddOns\Blizzard_AuctionHouseUI\Blizzard_AuctionHouseSellFrame.lua"]:353: in function UpdatePostState'
[string "@interface\AddOns\Blizzard_AuctionHouseUI\Blizzard_AuctionHouseItemSellFrame.lua"]:272: in function UpdatePostState' [string "@Interface\AddOns\Blizzard_AuctionHouseUI\Blizzard_AuctionHouseItemSellFrame.lua"]:213: in function SetSecondaryPriceInputEnabled'
[string "@interface\AddOns\Blizzard_AuctionHouseUI\Blizzard_AuctionHouseItemSellFrame.lua"]:37: in function UpdateState' [string "@Interface\AddOns\Blizzard_AuctionHouseUI\Blizzard_AuctionHouseItemSellFrame.lua"]:15: in function <...uctionHouseUI\Blizzard_AuctionHouseItemSellFrame.lua:13> [string "=[C]"]: in function Show'
[string "@interface\AddOns\Blizzard_AuctionHouseUI\Blizzard_AuctionHouseFrame.lua"]:489: in function <...izzard_AuctionHouseUI\Blizzard_AuctionHouseFrame.lua:449>
[string "=[C]"]: in function ?' [string "@Interface\SharedXML\Util.lua"]:1486: in function CallMethodOnNearestAncestor'
[string "@interface\AddOns\Blizzard_AuctionHouseUI\Blizzard_AuctionHouseTab.lua"]:31: in function <...Blizzard_AuctionHouseUI\Blizzard_AuctionHouseTab.lua:30>

Locals:

Error 2:
Message: bad argument #1 to '?' (Usage: local depositCost = C_AuctionHouse.CalculateItemDeposit(item, duration, quantity))
Time: Thu Sep 17 10:38:47 2020
Count: 1
Stack: bad argument #1 to '?' (Usage: local depositCost = C_AuctionHouse.CalculateItemDeposit(item, duration, quantity))
[string "=[C]"]: ?
[string "=[C]"]: in function CalculateItemDeposit' [string "@Interface\AddOns\Blizzard_AuctionHouseUI\Blizzard_AuctionHouseItemSellFrame.lua"]:303: in function GetDepositAmount'
[string "@interface\AddOns\Blizzard_AuctionHouseUI\Blizzard_AuctionHouseSellFrame.lua"]:487: in function CanPostItem' [string "@Interface\AddOns\Blizzard_AuctionHouseUI\Blizzard_AuctionHouseItemSellFrame.lua"]:332: in function CanPostItem'
[string "@interface\AddOns\Blizzard_AuctionHouseUI\Blizzard_AuctionHouseSellFrame.lua"]:476: in function UpdatePostButtonState' [string "@Interface\AddOns\Blizzard_AuctionHouseUI\Blizzard_AuctionHouseSellFrame.lua"]:336: in function OnEvent'
[string "@interface\AddOns\Blizzard_AuctionHouseUI\Blizzard_AuctionHouseItemSellFrame.lua"]:85: in function <...uctionHouseUI\Blizzard_AuctionHouseItemSellFrame.lua:84>
[string "=[C]"]: in function RefreshItemSearchResults' [string "@Interface\AddOns\Blizzard_AuctionHouseUI\Blizzard_AuctionHouseFrame.lua"]:729: in function RefreshSearchResults'
[string "@interface\AddOns\Blizzard_AuctionHouseUI\Blizzard_AuctionHouseItemSellFrame.lua"]:189: in function refreshResultsFunc' [string "@Interface\AddOns\Blizzard_AuctionHouseUI\Blizzard_AuctionHouseItemList.lua"]:211: in function <...ard_AuctionHouseUI\Blizzard_AuctionHouseItemList.lua:205> [string "=[C]"]: in function Show'
[string "@interface\AddOns\Blizzard_AuctionHouseUI\Blizzard_AuctionHouseFrame.lua"]:489: in function <...izzard_AuctionHouseUI\Blizzard_AuctionHouseFrame.lua:449>
[string "=[C]"]: in function ?' [string "@Interface\SharedXML\Util.lua"]:1486: in function CallMethodOnNearestAncestor'
[string "@interface\AddOns\Blizzard_AuctionHouseUI\Blizzard_AuctionHouseTab.lua"]:31: in function <...Blizzard_AuctionHouseUI\Blizzard_AuctionHouseTab.lua:30>

Locals:

Error 3:
Message: bad argument #1 to '?' (Usage: local depositCost = C_AuctionHouse.CalculateItemDeposit(item, duration, quantity))
Time: Thu Sep 17 10:38:48 2020
Count: 4
Stack: bad argument #1 to '?' (Usage: local depositCost = C_AuctionHouse.CalculateItemDeposit(item, duration, quantity))
[string "=[C]"]: ?
[string "=[C]"]: in function CalculateItemDeposit' [string "@Interface\AddOns\Blizzard_AuctionHouseUI\Blizzard_AuctionHouseItemSellFrame.lua"]:303: in function GetDepositAmount'
[string "@interface\AddOns\Blizzard_AuctionHouseUI\Blizzard_AuctionHouseSellFrame.lua"]:505: in function UpdateDeposit' [string "@Interface\AddOns\Blizzard_AuctionHouseUI\Blizzard_AuctionHouseSellFrame.lua"]:353: in function UpdatePostState'
[string "@interface\AddOns\Blizzard_AuctionHouseUI\Blizzard_AuctionHouseItemSellFrame.lua"]:272: in function UpdatePostState' [string "@Interface\AddOns\Blizzard_AuctionHouseUI\Blizzard_AuctionHouseSellFrame.lua"]:313: in function onValueChangedCallback'
[string "@interface\FrameXML\MoneyInputFrame.lua"]:327: in function `OnAmountChanged'
[string "@interface\FrameXML\MoneyInputFrame.lua"]:266: in function <Interface\FrameXML\MoneyInputFrame.lua:265>

Locals:

Error 4:
Message: bad argument #1 to '?' (Usage: local depositCost = C_AuctionHouse.CalculateItemDeposit(item, duration, quantity))
Time: Thu Sep 17 10:38:48 2020
Count: 1
Stack: bad argument #1 to '?' (Usage: local depositCost = C_AuctionHouse.CalculateItemDeposit(item, duration, quantity))
[string "=[C]"]: ?
[string "=[C]"]: in function CalculateItemDeposit' [string "@Interface\AddOns\Blizzard_AuctionHouseUI\Blizzard_AuctionHouseItemSellFrame.lua"]:303: in function GetDepositAmount'
[string "@interface\AddOns\Blizzard_AuctionHouseUI\Blizzard_AuctionHouseSellFrame.lua"]:487: in function CanPostItem' [string "@Interface\AddOns\Blizzard_AuctionHouseUI\Blizzard_AuctionHouseItemSellFrame.lua"]:332: in function CanPostItem'
[string "@interface\AddOns\Blizzard_AuctionHouseUI\Blizzard_AuctionHouseSellFrame.lua"]:476: in function UpdatePostButtonState' [string "@Interface\AddOns\Blizzard_AuctionHouseUI\Blizzard_AuctionHouseSellFrame.lua"]:336: in function OnEvent'
[string "@interface\AddOns\Blizzard_AuctionHouseUI\Blizzard_AuctionHouseItemSellFrame.lua"]:85: in function <...uctionHouseUI\Blizzard_AuctionHouseItemSellFrame.lua:84>

Locals: