I get error spam to the tune of

30x ...Ons/MinimalArchaeology/addon/components/Digsites.lua:1020: attempt to index local 'pin' (a nil value)
[string "@MinimalArchaeology/addon/components/Digsites.lua"]:1020: in function `ShowRaceIconsOnMap'
[string "@MinimalArchaeology/addon/core/Events.lua"]:153: in function `EventMain'
[string "@MinimalArchaeology/addon/components/Main.lua"]:175: in function <MinimalArchaeology/addon/components/Main.lua:174>

Locals:
self = <table> {
 wpButton = MinArchDigsitesAutoWayButton {
 }
 showAfterCombat = false
 frame = MinArchDigsites {
 }
}
uiMapID = 1439
count = 0
(for state) = <table> {
 1 = <table> {
 }
 2 = <table> {
 }
}
(for control) = 1
key = 1
digsite = <table> {
 researchSiteID = 299
 name = "Jaedenar Digsite"
 position = <table> {
 }
 textureIndex = 177
 poiBlobID = 56347
}
pin = nil
(*temporary) = 1.200000
(*temporary) = "Jaedenar Digsitepin"
(*temporary) = "pin"
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = <table> {
}
(*temporary) = nil
(*temporary) = "attempt to index local 'pin' (a nil value)"
SpamBlock = <table> {
 Jaedenar Digsitepin = 1
}
Common = <table> {
}

when zoning into Uldum from Stormwind portal

Taking a quick look through interface code I think I see where the problem is.

pins do not draw (or initialize data) on the DigSitePinTemplate unless your map is zoomed out to the continent level.
Zooming into the zone level means that your WorldMapFrame:EnumeratePinsByTemplate("DigSitePinTemplate") returns nothing / nil.

You'll probably refactor this to something following the addon structure (I can see a compatibility layer in shared\Common where some of that code would probably be moved to, but for the purpose of illustration something like this seems to fix the immediate problem
*Another option would be to "blindly" iterate both types of pinTemplates in AquirePin and return from whichever is populated.

Changing :ShowRaceIconsOnMap() to something like

local mapType = C_Map.GetMapInfo(uiMapID) and C_Map.GetMapInfo(uiMapID).mapType
for key, digsite in pairs(C_ResearchInfo.GetDigSitesForMap(uiMapID)) do
	local pin = AcquireMapPin(digsite.name, mapType);
	if not SpamBlock[digsite.name .. 'pin'] and (not pin) then
		Common:DisplayStatusMessage("Minimal Archaeology: Could not find pin for digsite "..digsite.name .. " " .. uiMapID)
		SpamBlock[digsite.name .. 'pin'] = 1
		return
	end

and AquireMapPin to

local function AcquireMapPin(nodeName, mapType)
	local pinTemplate
	if mapType == Enum.UIMapType.Continent then
		pinTemplate = "DigSitePinTemplate"
	elseif mapType == Enum.UIMapType.Zone then
		pinTemplate = "DigSiteBlobPinTemplate"
	end
	if pinTemplate then
		for pin in WorldMapFrame:EnumeratePinsByTemplate(pinTemplate) do
			if pin.name == nodeName then
				return pin
			end
		end
	end
end

stops the error at least.

The reason this doesn't work as is originally is because of this block in DigSiteDataProvider (Blizzard)

if(self:IsZoneMapType()) then
	-- Only use blob pins if we are zoomed into a zone on the world map
	local pin = self:GetMap():AcquirePin("DigSiteBlobPinTemplate", digSiteInfo);
	pin.digSiteInfo = digSiteInfo;
	pin:SetMapID(mapID);
else
	-- Create shovel icon pin
	self:GetMap():AcquirePin("DigSitePinTemplate", digSiteInfo);
end

Thanks for reporting this. Should be fixed in v11.1.0.4.

I noticed some loss of functionality with the new method so I ended up using my previous method for acquiring pins on Cata, since it doesn't seem to be causing the taint on Cata that was happening on Mainline.

Please feel free to reopen this issue if you encounter any errors after this update.