Sorry I do not know the Build, there is nothing to see if I open the configuration of PetTracker, but I always have the most newest versions from battle.net and Twitch. First I get the following error after login or start a pet battle. Then PetTracker is duplicating its entry in the Interface Panel. I have already seen more than a dozen entries in the Interface Panel.

Message: ...erface\AddOns\PetTracker\Features\BattleListener.lua:39: bad argument #1 to 'pairs' (table expected, got nil)
Time: Thu Oct 18 14:53:24 2018
Count: 3
Stack: ...erface\AddOns\PetTracker\Features\BattleListener.lua:39: bad argument #1 to 'pairs' (table expected, got nil)
[C]: ?
[C]: in function pairs' ...erface\AddOns\PetTracker\Features\BattleListener.lua:39: in function Upgrade'
...erface\AddOns\PetTracker\Features\BattleListener.lua:30: in function ?' Interface\AddOns\PetTracker\PetTracker.lua:40: in function ForAllModules'
Interface\AddOns\PetTracker\PetTracker.lua:54: in function `?'
Interface\AddOns\PetTracker\PetTracker.lua:21: in function <Interface\AddOns\PetTracker\PetTracker.lua:21>

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Fixed