There is probably more to it than this, but I narrowed down my problem to setting the tracking button's visibility to "never". With it on never, I get the following lua error whenever exiting a pet battle (and therefore re-showing the minimap). A reload is then required to keep the error from recurring in several circumstances such as mounting. This is with only Sexymap, BugSack, and BugGrabber enabled.

796x MultiBarLeft:SetScale(): Scale must be > 0
[string "=[C]"]: in function SetScaleBase' [string "@FrameXML/EditModeSystemTemplates.lua"]:114: in function SetScale'
[string "@FrameXML/EditModeManager.lua"]:612: in function UpdateRightActionBarPositions' [string "@FrameXML/EditModeManager.lua"]:582: in function UpdateActionBarLayout'
[string "@FrameXML/ActionBar.lua"]:342: in function UpdateVisibility' [string "@FrameXML/ActionBar.lua"]:176: in function SetShowGrid'
[string "@FrameXML/MultiActionBars.lua"]:85: in function MultiActionBar_ShowAllGrids' [string "@Blizzard_ClassTalentUI/Blizzard_ClassTalentFrameTemplate.lua"]:36: in function <..._ClassTalentUI/Blizzard_ClassTalentFrameTemplate.lua:24> [string "=[C]"]: in function Show'
[string "@FrameXML/UIParent.lua"]:2943: in function SetUIPanel' [string "@FrameXML/UIParent.lua"]:2747: in function ShowUIPanel'
[string "@FrameXML/UIParent.lua"]:2651: in function <FrameXML/UIParent.lua:2647>
[string "=[C]"]: in function SetAttribute' [string "@FrameXML/UIParent.lua"]:3253: in function <FrameXML/UIParent.lua:3232> [string "=[C]"]: ? [string "=[C]"]: ? [string "=[C]"]: in function ShowUIPanel'
[string "@FrameXML/UIParent.lua"]:947: in function `ToggleTalentFrame'
[string "TOGGLETALENTS"]:1: in function <[string "TOGGLETALENTS"]:1>

Locals:
(*temporary) = MultiBarLeft {
0 =
buttonPadding = 2
GetShowAllButtons = defined @FrameXML/ActionBar.lua:180
UpdateSystemSettingAlwaysShowButtons = defined @FrameXML/EditModeSystemTemplates.lua:923
UpdateMagnetismRegistration = defined @FrameXML/EditModeSystemTemplates.lua:654
GetSnapOffsets = defined @FrameXML/EditModeSystemTemplates.lua:532
UpdateFrameStrata = defined @FrameXML/ActionBar.lua:184
UpdateButtonArt = defined @FrameXML/EditModeSystemTemplates.lua:816
IsFrameAnchoredToMe = defined @FrameXML/EditModeSystemTemplates.lua:617
downKeys =

{
}
buttonTemplate = "MultiBar4ButtonTemplate"
ShowBase = defined =[C]:-1
IsShown = defined @FrameXML/ActionBar.lua:278
GetSelectionOffset = defined @FrameXML/EditModeSystemTemplates.lua:463
ResetToDefaultPosition = defined @FrameXML/EditModeSystemTemplates.lua:233
RefreshButtonArt = defined @FrameXML/EditModeSystemTemplates.lua:809
GetScaledSelectionSides = defined @FrameXML/EditModeSystemTemplates.lua:455
SelectSystem = defined @FrameXML/EditModeSystemTemplates.lua:686
buttonArtDirty = false
GetFrameMagneticEligibility = defined @FrameXML/EditModeSystemTemplates.lua:637
AddLayoutChildren = defined @SharedXML/LayoutFrame.lua:55
IsBelowFrame = defined @FrameXML/EditModeSystemTemplates.lua:422
UpdateSystemSettingIconSize = defined @FrameXML/EditModeSystemTemplates.lua:861
SetScaleBase = defined =[C]:-1
HasActiveChanges = defined @FrameXML/EditModeSystemTemplates.lua:344
GetScaledCenter = defined @FrameXML/EditModeSystemTemplates.lua:448
UpdateSystemSettingHideBarArt = defined @FrameXML/EditModeSystemTemplates.lua:890
UpdateDisplayInfoOptions = defined @FrameXML/EditModeSystemTemplates.lua:379
GetSystemName = defined @FrameXML/EditModeSystemTemplates.lua:747
ProcessMovementKey = defined @FrameXML/EditModeSystemTemplates.lua:39
GetSettingValueBool = defined @FrameXML/EditModeSystemTemplates.lua:359
OnKeyUp = defined @FrameXML/EditModeSystemTemplates.lua:89
IsLayoutFrame = defined @SharedXML/LayoutFrame.lua:36
DoesSettingValueEqual = defined @FrameXML/EditModeSystemTemplates.lua:363
MarkDirty = defined @SharedXML/LayoutFrame.lua:99
ShouldResetSettingsDialogAnchors = defined @FrameXML/EditModeSystemTemplates.lua:172
dirtySettings = {
}
UpdateGridLayout = defined @FrameXML/EditModeSystemTemplates.lua:795
IsToTheLeftOfFrame = defined @FrameXML/EditModeSystemTemplates.lua:404
GetSettingsDialogAnchor = defined @FrameXML/EditModeSystemTemplates.lua:388
hasActiveChanges = false
OnSystemLoad = defined @FrameXML/EditModeSystemTemplates.lua:3
ClearFrameSnap = defined @FrameXML/EditModeSystemTemplates.lua:576
GetCombinedCenterOffset = defined @FrameXML/EditModeSystemTemplates.lua:519
SetupSettingsDialogAnchor = defined @FrameXML/EditModeSystemTemplates.lua:332
IsShownOverride = defined @FrameXML/ActionBar.lua:278
dirty = false
SetPointBase = defined =[C]:-1
UpdateSystem = defined @FrameXML/EditModeSystemTemplates.lua:758
UpdateShownButtons = defined @FrameXML/ActionBar.lua:188
UpdateDirtySettings = defined @FrameXML/EditModeSystemTemplates.lua:193
BreakSnappedFrames = defined @FrameXML/EditModeSystemTemplates.lua:559
HideOverride = <func

This is with only Sexymap, BugSack, and BugGrabber enabled.

I already have all these addons installed.
I reset my SexyMap profile to default, only changed the tracking button to hidden.
Went into a pet battle, left it.
No error occured.
Since the error you posted doesn't mention SexyMap or the tracking button, I'm going to close this as unrelated to this addon.

The error appears to be related to Edit Mode. So I'd delete all your Edit Mode profiles, restart the game and see if the issue still occurs.
If you can figure out a reproducible path for me to try, feel free let me know.