Beta and PTR
Getting this from Dalaran in Broken Isles

1x Carbonite\NxMapGuide.lua:1499: bad argument #4 to 'format' (string expected, got nil)
[string "=[C]"]: in function format' [string "@Carbonite\NxMapGuide.lua"]:1499: in function UpdateMapGeneralIcons'
[string "@carbonite\NxMapGuide.lua"]:1596: in function ?' [string "@Carbonite\NxMap.lua"]:5077: in function Update'
[string "@carbonite\NxMap.lua"]:4010: in function <Carbonite\NxMap.lua:3894>

Locals:
(*temporary) = "%s
%s
%s %.1f %.1f"
(*temporary) = "Neutral Flight"
(*temporary) = "Krasus Landing, Dalaran (Legion)"
(*temporary) = nil
(*temporary) = 69.800000
(*temporary) = 51
(*temporary) = "string expected, got nil"

Also getting this if it helps

3x ...lizzard_MapCanvas\MapCanvas_ScrollContainerMixin.lua:426: attempt to index local 'layers' (a nil value)
[string "@Blizzard_MapCanvas\MapCanvas_ScrollContainerMixin.lua"]:426: in function CreateZoomLevels' [string "@Blizzard_MapCanvas\MapCanvas_ScrollContainerMixin.lua"]:413: in function OnCanvasSizeChanged'
[string "@Blizzard_MapCanvas\MapCanvas_ScrollContainerMixin.lua"]:404: in function SetMapID' [string "@Blizzard_MapCanvas\Blizzard_MapCanvas.lua"]:55: in function SetMapID'
[string "@carbonite\NxMap.lua"]:263: in function SetMapByID' [string "@Carbonite\NxMap.lua"]:9476: in function SetCurrentMap'
[string "@carbonite\NxMap.lua"]:6253: in function CheckWorldHotspotsType' [string "@Carbonite\NxMap.lua"]:6223: in function CheckWorldHotspots'
[string "@carbonite\NxMap.lua"]:4073: in function <Carbonite\NxMap.lua:3894>

Locals:
self = {
0 =
MarkCanvasDirty = defined @Blizzard_MapCanvas\MapCanvas_ScrollContainerMixin.lua:381
GetMinZoomViewRect = defined @Blizzard_MapCanvas\MapCanvas_ScrollContainerMixin.lua:550
GetNormalizedHorizontalScroll = defined @Blizzard_MapCanvas\MapCanvas_ScrollContainerMixin.lua:716
SetPanTarget = defined @Blizzard_MapCanvas\MapCanvas_ScrollContainerMixin.lua:583
DenormalizeVerticalSize = defined @Blizzard_MapCanvas\MapCanvas_ScrollContainerMixin.lua:741
IsAtMaxZoom = defined @Blizzard_MapCanvas\MapCanvas_ScrollContainerMixin.lua:652
AccumulateMouseDeltas = defined @Blizzard_MapCanvas\MapCanvas_ScrollContainerMixin.lua:245
ScalingMode = defined @Blizzard_MapCanvas\MapCanvas_ScrollContainerMixin.lua:290
GetMap = defined @Blizzard_MapCanvas\MapCanvas_ScrollContainerMixin.lua:664
IsZoomingIn = defined @Blizzard_MapCanvas\MapCanvas_ScrollContainerMixin.lua:644
ZoomOut = defined @Blizzard_MapCanvas\MapCanvas_ScrollContainerMixin.lua:604
ShouldZoomInstantly = defined @Blizzard_MapCanvas\MapCanvas_ScrollContainerMixin.lua:542
SetScalingMode = defined @Blizzard_MapCanvas\MapCanvas_ScrollContainerMixin.lua:286
targetScale = 1.693114
GetNormalizedCursorPosition = defined @Blizzard_MapCanvas\MapCanvas_ScrollContainerMixin.lua:774
TryPanOrZoomOnClick = defined @Blizzard_MapCanvas\MapCanvas_ScrollContainerMixin.lua:84
shouldPanOnClick = false
SetZoomTarget = defined @Blizzard_MapCanvas\MapCanvas_ScrollContainerMixin.lua:588
normalizedPanXLerpAmount = 0.150000
NormalizeUIPosition = defined @Blizzard_MapCanvas\MapCanvas_ScrollContainerMixin.lua:761
OnMouseUp = defined @Blizzard_MapCanvas\MapCanvas_ScrollContainerMixin.lua:102
MarkAreaTriggersDirty = defined @Blizzard_MapCanvas\MapCanvas_ScrollContainerMixin.lua:373
CalculateViewRect = defined @Blizzard_MapCanvas\MapCanvas_ScrollContainerMixin.lua:554
ResetZoom = defined @Blizzard_MapCanvas\MapCanvas_ScrollContainerMixin.lua:616
NormalizeHorizontalSize = defined @Blizzard_MapCanvas\MapCanvas_ScrollContainerMixin.lua:729
SetNormalizedHorizontalScroll = defined @Blizzard_MapCanvas\MapCanvas_ScrollContainerMixin.lua:711
OnLoad = defined @Blizzard_MapCanvas\MapCanvas_ScrollContainerMixin.lua:7
Child = {
}
zoomLevels =

Should be ok now ;) There may be more of this kind errors when PrePatch comes live. More people playing more testing ;)