This appears to only happen when I have a profession bag equipped:

Message: Interface/AddOns/BankStack/core.lua:489: attempt to call global 'GetContainerNumFreeSlots' (a nil value)
Time: Mon Nov 21 14:39:53 2022
Count: 1
Stack: Interface/AddOns/BankStack/core.lua:489: attempt to call global 'GetContainerNumFreeSlots' (a nil value)
[string "@Interface/AddOns/TradeSkillMaster/LibTSM/Service/ErrorHandler.lua"]:769: in function <...Ons/TradeSkillMaster/LibTSM/Service/ErrorHandler.lua:725>
[string "=(tail call)"]: ?
[string "=[C]"]: in function GetContainerNumFreeSlots' [string "@Interface/AddOns/BankStack/core.lua"]:489: in function CanItemGoInBag'
[string "@Interface/AddOns/BankStack/fill.lua"]:66: in function Fill' [string "@Interface/AddOns/BankStack/sort.lua"]:35: in function <Interface/AddOns/BankStack/sort.lua:12> [string "@Interface/AddOns/BankStack/core.lua"]:558: in function ?'
[string "@Interface/AddOns/BankStack/ldb.lua"]:68: in function `OnClick'
[string "@Interface/AddOns/BankStack/lib/LibDBIcon-1.0/LibDBIcon-1.0.lua"]:144: in function <...AddOns/BankStack/lib/LibDBIcon-1.0/LibDBIcon-1.0.lua:142>

Locals: errMsg = "Interface/AddOns/BankStack/core.lua:489: attempt to call global 'GetContainerNumFreeSlots' (a nil value)"
isBugGrabber = nil
tsmErrMsg = nil
oldModule = nil
private =

{
globalNameTranslation = {
}
FormatErrorMessageSection = defined @Interface/AddOns/TradeSkillMaster/LibTSM/Service/ErrorHandler.lua:525
ErrorHandler = defined @Interface/AddOns/TradeSkillMaster/LibTSM/Service/ErrorHandler.lua:134
origErrorHandler = defined @Interface/SharedXML/SharedBasicControls.lua:360
hitInternalError = false
CreateErrorFrame = defined @Interface/AddOns/TradeSkillMaster/LibTSM/Service/ErrorHandler.lua:544
num = 0
SanitizeString = defined @Interface/AddOns/TradeSkillMaster/LibTSM/Service/ErrorHandler.lua:518
AddonBlockedHandler = defined @Interface/AddOns/TradeSkillMaster/LibTSM/Service/ErrorHandler.lua:502
GetStackLevelInfo = defined @Interface/AddOns/TradeSkillMaster/LibTSM/Service/ErrorHandler.lua:344
ParseLocals = defined @Interface/AddOns/TradeSkillMaster/LibTSM/Service/ErrorHandler.lua:396
ignoreErrors = false
errorReports = {
}
IsTSMAddon = defined @Interface/AddOns/TradeSkillMaster/LibTSM/Service/ErrorHandler.lua:478
localLinesTemp = {
}
GetStackInfo = defined @Interface/AddOns/TradeSkillMaster/LibTSM/Service/ErrorHandler.lua:313
}
MAX_STACK_DEPTH = 50
OLD_TSM_MODULES = {
1 = "TradeSkillMaster_Accounting"
2 = "TradeSkillMaster_AuctionDB"
3 = "TradeSkillMaster_Auctioning"
4 = "TradeSkillMaster_Crafting"
5 = "TradeSkillMaster_Destroying"
6 = "TradeSkillMaster_Mailing"
7 = "TradeSkillMaster_Shopping"
8 = "TradeSkillMaster_Vendoring"
9 = "TradeSkillMaster_Warehousing"
}