I just ran The Necrotic Wake, before fighting the next to last boss, you're taken up into the flying Necropolis.
As soon as I landed inside I started receiving a flood of error messages, unfortunately I wasn't able to copy it at the time because I couldn't continue to do the instance until WoW asked if I wanted to Disable all my addons because of the error.

I tried to locate a log file but was unable to find one. Sorry that I can't provide more details. But I do know that it was specifically referring to Carbonite and NXMap. It was basically indicating that a variable or index was undefined.

Copied from the https://www.curseforge.com/ page.

This sounds like a reported error on WoWInterface forums.. Copied below.. This error does not use the latest from Git but I do not think it matters as the error line in 12271 instead of the one listed in the report and could be the zone not in database.

Everytime we reach the final two bosses above the main floor, this error constantly gets thrown

34946x Carbonite\NxMapData.lua:12270: attempt to index field '?' (a nil value)
[string "@carbonite\NxMapData.lua"]:12270: in function GetZoneInfo' [string "@Carbonite\NxMap.lua"]:9855: in function IsInstanceMap'
[string "@carbonite\NxMap.lua"]:5328: in function SwitchRealMap' [string "@Carbonite\NxMap.lua"]:4512: in function Update'
[string "@carbonite\NxMap.lua"]:4021: in function <Carbonite\NxMap.lua:3905>

Locals:
self =

Shit... no time to debug it... Ill try to do the fix but u need to test it.

I can try and test it, let me know when you push the update.

Edit: Follow Mikepauers fix below instead to get it working properly.

If you edit "NxMapData.lua" and add the following around line 1655 (you'll see where it could go, but anywhere around this will be fine).

[1667] = {
	Scale = 1,
	X = -341.75,
	Y = 312,
	Name = L["The Necrotic Wake - Stichwerks"],
	BaseMap = 1667,
	Alpha = .85,
	MapLevel = 1,
},
[1668] = {
	Scale = 1,
	X = -341.75,
	Y = 312,
	Name = L["The Necrotic Wake - Zolramus"],
	BaseMap = 1668,
	Alpha = .85,
	MapLevel = 1,
},

This fixes the error messages, but it does not show the dungeon canvas map for these two encounters, as I couldn't figure out how.

Im little busy right now. But ill make fix.

@instant0 this is just a workaround, but thanks.

As it's a dungeon they shouldn't be in NxMapData, but instead in Data\zones.lua

Something like:
[1666] = L["The Necrotic Wake"] .. "|50|60|3|5|1533|40.13|55.24|5",
[1667] = L["The Necrotic Wake - Stichwerks"] .. "|50|60|3|5|1533|40.13|55.24|0",
[1668] = L["The Necrotic Wake - Zolramus"] .. "|50|60|3|5|1533|40.13|55.24|0",

@mikepauer it can be, there is bug in auto zone adding function that i did added.

I'd try and do fixes, but right now no computer.. been waiting 2 months now for CPU delivery so I can build and get back in... hopefully not much longer so your not doing it alone.

@mikepauer Thanks, adding those and removing my workaround fixed it and added the map information correctly.
Just tested it now.

@instant0 yes this needs to work, i will add this to Carbonite. But i need to fix this automatic zone adding too ;)