This error pops up every few seconds, and had happened six times before I logged in here; by the time I finished writing this ticket, that number had gone up to 33.

This is the full error I get; apologies for how long it is, but that's down to the Lua error window.

Message: Interface\AddOns\BadBoy_CCleaner\BadBoy_CCleaner.lua:24: attempt to call upvalue 'BadBoyIsFriendly' (a nil value)
Time: Mon Dec 9 21:52:16 2019
Count: 6
Stack: Interface\AddOns\BadBoy_CCleaner\BadBoy_CCleaner.lua:24: attempt to call upvalue 'BadBoyIsFriendly' (a nil value)
Interface\AddOns\BadBoy_CCleaner\BadBoy_CCleaner.lua:24: in function filterFunc' Interface\FrameXML\ChatFrame.lua:2990: in function ChatFrame_MessageEventHandler'
Interface\FrameXML\ChatFrame.lua:2713: in function <Interface\FrameXML\ChatFrame.lua:2706>
(tail call): ?
[string ":OnEvent"]:1: in function <[string ":OnEvent"]:1>

Locals: _ = ChatFrame1 {
GatherSelectedText = defined =[C]:-1
RefreshIfNecessary = defined =[C]:-1
OnPostShow = defined =[C]:-1
CalculateLineAlphaValueFromTimestamp = defined =[C]:-1
ScrollUp = defined =[C]:-1
tellTimer = 1294093.825000
fadeDurationSecs = 3
GetFading = defined =[C]:-1
IsTextCopyable = defined =[C]:-1
shouldFadeAfterInactivity = true
SetIndentedWordWrap = defined =[C]:-1
GetJustifyV = defined =[C]:-1
ScrollToBottom = defined =[C]:-1
GetMaxLines = defined =[C]:-1
GetIndentedWordWrap = defined =[C]:-1
buttonSide = "left"
GetFont = defined =[C]:-1
checkedGMOTD = true
SetMaxLines = defined =[C]:-1
CalculateSelectingCharacterIndicesForVisibleLine = defined =[C]:-1
OnPostUpdate = defined =[C]:-1
RefreshDisplay = defined =[C]:-1
SetFontObject = defined =[C]:-1
textIsCopyable = false
SetOnScrollChangedCallback = defined =[C]:-1
CalculateNumVisibleLines = defined =[C]:-1
overrideFadeTimestamp = 1293850.786000
MarkDisplayDirty = defined =[C]:-1
GetMessageInfo = defined =[C]:-1
GetOnScrollChangedCallback = defined =[C]:-1
AtTop = defined =[C]:-1
GetFontObject = defined =[C]:-1
fontStringPool =

{
}
CanEffectivelyFade = defined =[C]:-1
OnPreSizeChanged = defined =[C]:-1
GetScrollOffset = defined =[C]:-1
GetSpacing = defined =[C]:-1
OnPreLoad = defined =[C]:-1
SetSpacing = defined =[C]:-1
name = "General"
CalculateLineSpacing = defined =[C]:-1
AddMessage = defined =[C]:-1
InitializeFontableFrame = defined =[C]:-1
GetShadowColor = defined =[C]:-1
isUninteractable = false
SetOnTextCopiedCallback = defined =[C]:-1
mouseOutTime = 0
RemoveMessagesByPredicate = defined =[C]:-1
TransformMessages = defined =[C]:-1
SetShadowColor = defined =[C]:-1
buttonFrame = ChatFrame1ButtonFrame {
}
HasFontObject = defined =[C]:-1
isDocked = 1
GetOnTextCopiedCallback = defined =[C]:-1
SetFading = defined =[C]:-1
OnPostHide = defined =[C]:-1
alternativeDefaultLanguage = "Common"
isInitialized = 1
GetNumVisibleLines = defined =[C]:-1
GetInsertMode = defined =[C]:-1
SetTimeVisible = defined =[C]:-1
hasOwnFontObject = true
Clear = defined =[C]:-1
oldAlpha = 0
channelList = {
}
GetTimeVisible = defined =[C]:-1
MarkLayoutDirty = defined =[C]:-1
SetTextCopyable = defined =[C]:-1
BackFillMessage = defined =[C]:-1
UnpackageEntry = defined =[C]:-1
FontStringContainer = {
}
SetShadowOffset = defined =[C]:-1
messageTypeList = {
}
flashTimer = 0
timeVisibleSecs = 120
PackageEntry = defined =[C]:-1
MakeFontObjectCustom = defined =[C]:-1
fontObject = table: 0000017B1EB5C0F0 {
}
SetInsertMode = defined =[C]:-1
mouseInTime = 0
UpdateSelectingText = defined =[C]:-1
zoneChannelList = {
}
SetScrollOffset =