Question in regards to string.lower

[Sharlikran]

function Harvest.IsValidBottle(name)
    for k, v in pairs(Harvest.bottle) do
		d("v name :" .. v)
		d("name :" .. name)
        if v == name then
            return true
        end
    end

    return false
end

I though the above function was working perfectly yesterday. However, I reverted changes to stick with the original authors syntax.
The entire function:

Warning: Spoiler

function Harvest.OnLootReceived( eventCode, receivedBy, objectName, stackCount, soundCategory, lootType, lootedBySelf )
	if not Harvest.PlayetInteracting or not lootedBySelf then
		if Harvest.settings.debug then
			if not Harvest.PlayetInteracting then
			 d("Not Harvesting")
			end
			if  not lootedBySelf then
			d("Not Looted by self")
			end
		end
		return
	end
	
	local zone, x, y = Harvest.GetLocation()
	local itemId
	_, _, _, itemId = ZO_LinkHandler_ParseLink( objectName ) --name, color, type, id, +19 other attributes
	itemId = tonumber( itemId )
	if Harvest.settings.debug then
		d("OnLootReceived ItemNumber:" .. itemId)
		d("OnLootReceived ItemName" .. objectName)
	end
	local profession = Harvest.GetProfessionType(itemId, objectName)
	
	if (profession < 1) then 
		if Harvest.settings.debug then
			d("Valid profession information Not found!")
		end
		return
	end
	
	Harvest.saveData( zone, x, y, profession, objectName, itemID )
	Harvest.RefreshPins( profession )
end

_, _, _, itemId = ZO_LinkHandler_ParseLink( objectName ) --name, color, type, id, +19 other attributes

He uses that to do something and I don't quite get. The function is on the wiki but no explanation as to what it does. Whatever it's doing it's preventing the routine from comparing the names. So I changed the Boolean routine to this thinking it would be enough.

function Harvest.IsValidBottle(name)
    for k, v in pairs(Harvest.bottle) do
		d("v name :" .. v)
		d("name :" .. string.lower(name))
        if v == string.lower(name) then
            return true
        end
    end

    return false
end

When I do that then the debug routine returns this.

:hFFFFFF:item:1187:1:13:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:hclear waterh

I fixed it by making a global variable. However, for my sanity does anyone know why that's happening?