Running Software (issues missing this information will be deleted):

• Addon version: 9.0.0
• Server patch: 9.0

Have you read the changelog? (please don't waste our time)
Yes.

Describe the bug
Interacting with some objects causes a PetTracker error to appear.

To Reproduce

1. Go to Boralus
2. Click on the mission table
3. See error

The problem is reproduced systematically in Boralus, as well as when clicking on Draenor Garrison mission table. No mission management addons is installed. I have randomly seen it when clicking on some other objects, but with a mission table it's systematic.

Expected behaviour
No error appears.

Screenshots

Error Logs
Message: ...ce\AddOns\PetTracker\addons\main\features\gossip.lua:39: attempt to index field 'buttons' (a nil value)
Time: Thu Oct 15 23:31:27 2020
Count: 3
Stack: ...ce\AddOns\PetTracker\addons\main\features\gossip.lua:39: attempt to index field 'buttons' (a nil value)
[string "@interface\AddOns\PetTracker\addons\main\features\gossip.lua"]:39: in function <...ce\AddOns\PetTracker\addons\main\features\gossip.lua:38>
[string "=[C]"]: in function SelectOption' [string "@Interface\FrameXML\GossipFrame.lua"]:74: in function GossipFrame_HandleShow'
[string "@interface\FrameXML\CustomGossipFrameBase.lua"]:47: in function `HandleOpenEvent'
[string "@interface\FrameXML\CustomGossipFrameBase.lua"]:39: in function <Interface\FrameXML\CustomGossipFrameBase.lua:37>

Locals: index = 1
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = "attempt to index field 'buttons' (a nil value)"
ADDON = "PetTracker"
Addon =

{
SendSignal = defined @interface\AddOns\Bagnon\common\Wildpants\libs\WildAddon-1.0\WildAddon-1.0.lua:82
Gossip = {
}
SpeciePin = {
}
Tutorials = {
}
UnregisterAllEvents = defined @interface\AddOns\Bagnon\common\Wildpants\libs\CallbackHandler-1.0\CallbackHandler-1.0.lua:174
Options = {
}
Enemy = {
}
sets = {
}
state = {
}
MaxLevel = 25
GetColor = defined @interface\AddOns\PetTracker\addons\main\main.lua:66
Entity = {
}
Species = {
}
Delaying = defined @interface\AddOns\Bagnon\common\Wildpants\libs\MutexDelay-1.0\MutexDelay-1.0.lua:46
JournalSlot = {
}
Rival = {
}
Tooltips = {
}
OnPetsChanged = defined @interface\AddOns\PetTracker\addons\main\main.lua:53
NewModule = defined @interface\AddOns\Bagnon\common\Wildpants\libs\WildAddon-1.0\WildAddon-1.0.lua:68
MultiTip = {
}
MapCanvas = {
}
Tracker = {
}
Stables = {
}
AbilityDisplay = {
}
TextLine = {
}
Search = defined @interface\AddOns\PetTracker\addons\main\api\search.lua:26
StablePin = {
}
RivalInfo = {
}
Pin = {
}
Delay = defined @interface\AddOns\Bagnon\common\Wildpants\libs\MutexDelay-1.0\MutexDelay-1.0.lua:27
Tag = "PETTRACKER_"
BattleSlot = {
}
Pet = {
}
AbilityAction = {
}
TextList = {
}
MaxQuality = 6
UnregisterMessage = defined @interface\AddOns\Bagnon\common\Wildpants\libs\CallbackHandler-1.0\CallbackHandler-1.0.lua:153
ProgressBar = {
}
SpecieStats = {
}
RivalPin = {
}
MapSearch = {
}
Specie = {
}
PetSlot = {
}
Ability = {
}
Rivals = {
}
Base = {
}
Predict = {
}
UnregisterSignal = defined @interface\AddOns\Bagnon\common\Wildpants\libs\WildAddon-1.0\WildAddon-1.0.lua:78
Maps = {
}
SpecieBreeds = {
}
RegisterMessage = defined @interface\AddOns\Bagnon\common\Wildpants\libs\CallbackHandler-1.0\CallbackHandler-1.0.lua:90
RegisterEvent = defined @interface\AddOns\Bagnon\common\Wildpants\libs\CallbackHandler-1.0\CallbackHandler-1.0.lua:90
UnregisterAllMessages = defined @interface\AddOns\Bagnon\common\Wildpants\libs\CallbackHandler-1.0\CallbackHandler-1.0.lua:174
OnBattle = defined @interface\AddOns\PetTracker\addons\main\main.lua:57
Breeds = {
}
AbilityButton = {
}
OnEnable = defined @interface\AddOns\PetTracker\addons\main\main.lua:26
Name = "PetTracker"
RivalOrder = {
}
SendMessage = defined @interface\AddOns\Bagnon\common\Wildpants\libs\CallbackHandler-1.0\CallbackHandler-1.0.lua:59
RegisterSignal = defined @interface\AddOns\Bagnon\common\Wildpants\libs\WildAddon-1.0\WildAddon-1.0.lua:74
UnregisterEvent = defined @interface\AddOns\Bagnon\c