Describe the bug
Updated to 10.2.20. Working on the Blue Dragon Flight United Gain story quest chain. As soon as I reached the later part of the chain where you enter the Azure Archives, upon accepting the quest and entering the instance the following error occurred. A second occurrence of the error happened again after finishing the quest and exiting the instance. Thanks.

Do you have an error log of what happened?
2x DBM-Core/DBM-Core.lua:7209: attempt to concatenate local 'currentMapID' (a nil value)
[string "@DBM-Core/DBM-Core.lua"]:7209: in function `handler'
[string "@DBM-Core/DBM-Core.lua"]:1140: in function <DBM-Core/DBM-Core.lua:1127>

Locals:
self =

{
SelectGossip = defined @DBM-Core/DBM-Core.lua:2972
GetUnitIdFromCID = defined @DBM-Core/DBM-Core.lua:2862
CHAT_MSG_ADDON_LOGGED = defined @DBM-Core/DBM-Core.lua:4796
IsRetail = defined @DBM-Core/DBM-Core.lua:7558
StopLogging = defined @DBM-Core/DBM-Core.lua:6073
FindScenarioIDs = defined @DBM-Core/DBM-Core.lua:7135
GetNumGuildPlayersInZone = defined @DBM-Core/DBM-Core.lua:2600
VibrateController = defined @DBM-Core/DBM-Core.lua:7101
FindDungeonMapIDs = defined @DBM-Core/DBM-Core.lua:7127
GetUnitIdFromGUID = defined @DBM-Core/DBM-Core.lua:2684
CopyProfile = defined @DBM-Core/DBM-Core.lua:2066
CHAT_MSG_MONSTER_EMOTE = defined @DBM-Core/DBM-Core.lua:5151
CHAT_MSG_WHISPER = defined @DBM-Core/DBM-Core.lua:6862
SendPVPTimers = defined @DBM-Core/DBM-Core.lua:6657
DeleteProfile = defined @DBM-Core/DBM-Core.lua:2083
DungeonMusic = {
}
ShowUpdateReminder = defined @DBM-Core/modules/UpdateReminder.lua:80
GetRaidRoster = defined @DBM-Core/DBM-Core.lua:2639
PLAYER_REGEN_DISABLED = defined @DBM-Core/DBM-Core.lua:4913
FireEvent = defined @DBM-Core/DBM-Core.lua:1974
CreateModLocalization = defined @DBM-Core/modules/objects/Localization.lua:99
SCENARIO_COMPLETED = defined @DBM-Core/DBM-Core.lua:3645
IsEnabled = defined @DBM-Core/DBM-Core.lua:6943
GetMyPlayerInfo = defined @DBM-Core/DBM-Core.lua:2707
BuildVoiceCountdownCache = defined @DBM-Core/DBM-Core.lua:10554
ADDON_LOADED = defined @DBM-Core/DBM-Core.lua:1638
lastAntiSpamFLASH = 442448.566000
IconNumToTexture = defined @DBM-Core/DBM-Core.lua:7116
ReceiveVariableInfo = defined @DBM-Core/DBM-Core.lua:6607
registeredUnitEvents = {
}
BattleMusic = {
}
VoiceVersions = {
}
INSTANCE_GROUP_SIZE_CHANGED = defined @DBM-Core/DBM-Core.lua:2571
Voices = {
}
AddDefeatSound = defined @DBM-Core/modules/Sounds.lua:123
AddOns = {
}
SortByMeleeRoster = defined @DBM-Core/DBM-Core.lua:8050
Options = {
}
GetBossUnitId = defined @DBM-Core/DBM-Core.lua:2844
GetModLocalization = defined @DBM-Core/modules/objects/Localization.lua:116
AddDefaultOptions = defined @DBM-Core/DBM-Core.lua:2995
UPDATE_MOUSEOVER_UNIT = defined @DBM-Core/DBM-Core.lua:4005
ZONE_CHANGED_NEW_AREA = defined @DBM-Core/DBM-Core.lua:3850
CINEMATIC_START = defined @DBM-Core/DBM-Core.lua:7202
FilterRaidBossEmote = defined @DBM-Core/DBM-Core.lua:1473
RequestTimers = defined @DBM-Core/DBM-Core.lua:6554
GetMusic = defined @DBM-Core/modules/Sounds.lua:245
Music = {
}
SortByGroup = defined @DBM-Core/DBM-Core.lua:7999
GetBattleMusic = defined @DBM-Core/modules/Sounds.lua:211
RAID_BOSS_WHISPER = defined @DBM-Core/DBM-Core.lua:5173
UPDATE_BATTLEFIELD_STATUS = defined @DBM-Core/DBM-Core.lua:3623
GetDungeonMusic = defined @DBM-Core/modules/Sounds.lua:163
CheckNearby = defined @

To Reproduce
Working on the United Again storyline
Accepted The Last Conflict quest in the chain.
Entered the Azure Vault instance. (First occurrence of error)
Finished Quest and exited instance (second occurrence of error)

Screenshots
N/A

Did you try having DeadlyBossMods as the only enabled addon and everything else (especially something like ElvUI) disabled?
No

Which version of DeadlyBossMods are you using?
10.2.20

Was it working in a previous version? If yes, which was the last good one?
Yes. No error occurred when running it using 10.2.19 that I recall.

Additional context