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

• Addon version: 10.1
• Server patch: 10.1.0.49741

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

Describe the bug
A clear and concise description of what the bug is.

To Reproduce
Steps to reproduce the behaviour:

1. Log in
2. LUA error

Expected behaviour
A clear and concise description of what you expected to happen.
Log in and have no LUA error.

Screenshots
If applicable, add screenshots to help explain your problem.

Error Logs
Type /console scriptErrors 1 in the chat and reload the game. If an error window appears, write here the message with ID: 1 (labelled 1/X). This is generally NOT the message that the window shows by default.

8x ...PetTracker/libs/Sushi-3.1-5/classes/drops/Dropdown.lua:148: calling 'IsMouseOver' on bad self (Usage: local isMouseOver = self:IsMouseOver([offsetTop, offsetBottom, offsetLeft, offsetRight]))
[string "=[C]"]: in function `IsMouseOver'
[string "@PetTracker/libs/Sushi-3.1-5/classes/drops/Dropdown.lua"]:148: in function <...PetTracker/libs/Sushi-3.1/classes/drops/Dropdown.lua:147>
[string "@PetTracker/libs/Sushi-3.1-5/classes/drops/Dropdown.lua"]:153: in function <...PetTracker/libs/Sushi-3.1/classes/drops/Dropdown.lua:147>
[string "=(tail call)"]: ?
[string "@PetTracker/libs/Sushi-3.1-5/classes/drops/Dropdown.lua"]:93: in function <...PetTracker/libs/Sushi-3.1/classes/drops/Dropdown.lua:92>

Locals:
(*temporary) = SimpleCheckout {
0 =
RightOutside = Line {
}
RightInside = Line {
}
Background = Frame {
}
CalculateDesiredSize = defined @Blizzard_StoreUI/Blizzard_SimpleCheckout.lua:101
OnShow = defined @Blizzard_StoreUI/Blizzard_SimpleCheckout.lua:54
OnLoad = defined @Blizzard_StoreUI/Blizzard_SimpleCheckout.lua:25
OnHide = defined @Blizzard_StoreUI/Blizzard_SimpleCheckout.lua:61
LeftOutside = Line {
}
OnExternalLink = defined @Blizzard_StoreUI/Blizzard_SimpleCheckout.lua:83
TopInside = Line {
}
BottomOutside = Line {
}
CloseButton = Button {
}
TopOutside = Line {
}
BottomInside = Line {
}
OnEvent = defined @Blizzard_StoreUI/Blizzard_SimpleCheckout.lua:29
LeftInside = Line {
}
RecalculateSize = defined @Blizzard_StoreUI/Blizzard_SimpleCheckout.lua:139
OnRequestNewSize = defined @Blizzard_StoreUI/Blizzard_SimpleCheckout.lua:75
}

Additional context
Add any other context about the problem here.

Weeks later and still getting this error.
31x ...PetTracker/libs/Sushi-3.1-5/classes/drops/Dropdown.lua:148: calling 'IsMouseOver' on bad self (Usage: local isMouseOver = self:IsMouseOver([offsetTop, offsetBottom, offsetLeft, offsetRight]))
[string "=[C]"]: in function `IsMouseOver'
[string "@PetTracker/libs/Sushi-3.1-5/classes/drops/Dropdown.lua"]:148: in function <...PetTracker/libs/Sushi-3.1/classes/drops/Dropdown.lua:147>
[string "@PetTracker/libs/Sushi-3.1-5/classes/drops/Dropdown.lua"]:153: in function <...PetTracker/libs/Sushi-3.1/classes/drops/Dropdown.lua:147>
[string "=(tail call)"]: ?
[string "@PetTracker/libs/Sushi-3.1-5/classes/drops/Dropdown.lua"]:93: in function <...PetTracker/libs/Sushi-3.1/classes/drops/Dropdown.lua:92>

Locals:
(*temporary) = SimpleCheckout {
0 =
RightOutside = Line {
}
RightInside = Line {
}
Background = Frame {
}
CalculateDesiredSize = defined @Blizzard_StoreUI/Blizzard_SimpleCheckout.lua:101
OnShow = defined @Blizzard_StoreUI/Blizzard_SimpleCheckout.lua:54
OnLoad = defined @Blizzard_StoreUI/Blizzard_SimpleCheckout.lua:25
OnHide = defined @Blizzard_StoreUI/Blizzard_SimpleCheckout.lua:61
LeftOutside = Line {
}
OnExternalLink = defined @Blizzard_StoreUI/Blizzard_SimpleCheckout.lua:83
TopInside = Line {
}
BottomOutside = Line {
}
CloseButton = Button {
}
TopOutside = Line {
}
BottomInside = Line {
}
OnEvent = defined @Blizzard_StoreUI/Blizzard_SimpleCheckout.lua:29
LeftInside = Line {
}
RecalculateSize = defined @Blizzard_StoreUI/Blizzard_SimpleCheckout.lua:139
OnRequestNewSize = defined @Blizzard_StoreUI/Blizzard_SimpleCheckout.lua:75
}

If you just want the tracker on the map, I have created another addon without all the other stuff, that doesn't have all these errors.
It seems like this addon is just kept alive to get patreon supporters.
Have a look at Battle Pet Completionist, if you just want the map tracker.