This popped at the start of the encounter, on both Heroic and Mythic difficulties:

Message: BigWigs: Module "The Grand Menagerie" tried to register event "CHAT_MSG_MONSTER_SAY" to the function "CHAT_MSG_MONSTER_SAY" but the event is in the middle of dispatching.
Time: Sun Jul 6 11:58:17 2025
Count: 1
Stack:
[Interface/AddOns/LittleWigs_Shadowlands/Tazavesh/Trash.lua]:280: in function '?'
[Interface/AddOns/BigWigs_Core/Core.lua]:57: in function <Interface/AddOns/BigWigs_Core/Core.lua:51>

Locals:
self =

{
enableMobs = {
}
enabled = true
optionHeaders = {
}
instanceId = 2441
db = {
}
colorOptions = {
}
name = "BigWigs_Bosses_Tazavesh Trash"
toggleDefaults = {
}
toggleOptions = {
}
sayCountdowns = {
}
soundOptions = {
}
localization = {
}
displayName = "Trash"
moduleName = "Tazavesh Trash"
}
event = "CHAT_MSG_MONSTER_SAY"
msg = "Now for the item you have all been awaiting! The allegedly demon-cursed Edge of Oblivion!"
menagerieModule = {
colorOptions = {
}
enableMobs = {
}
enabled = true
journalId = 2454
name = "BigWigs_Bosses_The Grand Menagerie"
localization = {
}
toggleDefaults = {
}
engageId = 2441
sayCountdowns = {
}
soundOptions = {
}
db = {
}
toggleOptions = {
}
instanceId = 2441
displayName = "The Grand Menagerie"
stage = 1
respawnTime = 30
moduleName = "The Grand Menagerie"
}
L = {
trading_game = "Trading Game"
custom_on_portal_autotalk_desc = "Instantly open portals back to the entrance when talking to Broker NPCs."
interrogation_specialist = "Interrogation Specialist"
armored_overseer_tracker_zokorss = "Armored Overseer / Tracker Zo'korss"
defective_sorter = "Defective Sorter"
devoted_accomplice = "Devoted Accomplice"
stormforged_guardian = "Stormforged Guardian"
cartel_smuggler = "Cartel Smuggler"
portal_authority = "Tazavesh Portal Authority"
market_peacekeeper = "Market Peacekeeper"
commerce_enforcer_commander_zofar = "Commerce Enforcer / Commander Zo'far"
custom_on_trading_game_autotalk_desc = "Instantly select the right password after the Trading Game has been completed."
portalmancer_zohonn = "Portalmancer Zo'honn"
menagerie_warmup_trigger = "Now for the item you have all been awaiting! The allegedly demon-cursed Edge of Oblivion!"
tracker_zokorss = "Tracker Zo'korss"
commander_zofar = "Commander Zo'far"
support_officer = "Support Officer"
murkbrine_scalebinder = "Murkbrine Scalebinder"
focused_ritualist = "Focused Ritualist"
adorned_starseer = "Adorned Starseer"
burly_deckhand = "Burly Deckhand"
custom_on_portal_autotalk_icon = "Interface\AddOns\BigWigs\Media\Icons\Menus\Say"
coastwalker_goliath = "Coastwalker Goliath"
enraged_direhorn = "Enraged Direhorn"
commerce_enforcer = "Commerce Enforcer"
murkbrine_shellcrusher = "Murkbrine Shellcrusher"
tazavesh_soleahs_gambit = "Tazavesh: So'leah's Gambit"
password_triggers = {
}
trading_game_desc = "Alerts with the right password during the Trading Game."
custom_on_trading_game_autotalk = "Automatic NPC interaction"
custom_on_portal_autotalk = "Automatic NPC interaction"
cartel_muscle = "Cartel Muscle"
veteran_sparkcaster = "Veteran Sparkcaster"
custom_on_trading_game_autotalk_icon = "Interface\AddOns\BigWigs\Media\Icons\Menus\Say"
zophex_warmup_trigger = "Surrender... all... contraband..."
ancient_core_hound = "Ancient Core Hound"
soazmi_warmup_trigger = "Excuse our intrusion, So'leah. I hope we caught you at an inconvenient time."
}
passwordId = 53267