registerForDefaults doesn't work as expected

[Lykeion]

Greetings.

I've recently coded my first addon Much Smarter AutoLoot and seems it gets the job done not bad. Yet I faced a problem that I can't make the build-in function registerForDefaults, which is provided by LibAddonMenu works on my addon.
When I click the Default button in my addon panel and confirm in the confirmation box, nothing happens. The options aren't set to default, nor does the confirmation box disappear. Literally, nothing happens.

I can't find out what causes this problem. I gave every panel option default and set registerForDefaults true, but for some reason, LibAddonMenu cannot reset them.

...
local panelData = 
{
	type = "panel",
	name = GetString(MSAL_PANEL_NAME),
	displayName = GetString(MSAL_PANEL_DISPLAYNAME),
	author = "|c215895Lykeion|r",
	version = "|ccc922f2.2.0|r",
	slashCommand = "/msal",
	registerForRefresh = true,
	registerForDefaults = true
}

...

local optionsData = 
{	
...
	{
		type = "submenu",
		name = GetString(MSAL_LOOT_FILTERS),
		controls = {
			[1] = {
				type = "slider",
				name = GetString(MSAL_QUALITY_THRESHOLD),
				tooltip = GetString(MSAL_QUALITY_THRESHOLD_TOOLTIP),
				min = 1,
				max = 5,
				step = 1,
				getFunc = function() return db.minimumQuality end,
				setFunc = function(value) db.minimumQuality = value end,
				default = 1,
			},
			[2] = {
				type = "slider",
				name = GetString(MSAL_VALUE_THRESHOLD),
				tooltip = GetString(MSAL_VALUE_THRESHOLD_TOOLTIP),
				min = 0,
				max = 10000,
				getFunc = function() return db.minimumValue end,
				setFunc = function(value) db.minimumValue = value end,
				default = 10,
			},
			[3] = {
				type = "dropdown",
				name = GetString(MSAL_ORNATE_ITEMS),
				tooltip = GetString(MSAL_ORNATE_INTRCATE_TOOLTIP),
				choices = defaultChoices,
				choicesValues = defaultChoicesValues,
				getFunc = function() return db.filters.ornate end,
				setFunc = function(value) db.filters.ornate = value end,
				default = "always loot",
			},
			[4] = {
				type = "dropdown",
				name = GetString(MSAL_INTRICATE_ITEMS),
				tooltip = GetString(MSAL_ORNATE_INTRCATE_TOOLTIP),
				choices = defaultChoices,
				choicesValues = defaultChoicesValues,
				getFunc = function() return db.filters.intricate end,
				setFunc = function(value) db.filters.intricate = value end,
				default = "always loot",
			},
		...
	}
	...
}

LAM2:RegisterAddonPanel("MuchSmarterAutoLootOptions", panelData)
LAM2:RegisterOptionControls("MuchSmarterAutoLootOptions", optionsData)
...

My SVs typically look like this. I don't know whether SVs' structure could make an impact on registerForDefaults' function, but someone told me it is good to keep nested tables away from SVs if you want to reset options to default later. I tried expanding the nested table["filters"] in my SVs but it didn't solve this problem. Considering nested tables haven't raised any problems till now, I keep them intact in SVs temporarily.

MSAL_VARS =
{
    ["NA Megaserver"] = 
    {
        ["@userId"] = 
        {
            ["Id"] = 
            {
            ["$AccountWide"] = 
            {
                ["Account"] = 
                {
                    ["lootStolen"] = false,
                    ["allowDestroy"] = false,
                    ["minimumQuality"] = 4,
                    ["printItems"] = false,
                    ["filters"] = 
                    {
                        ["potions"] = "always loot",
                        ["collectibles"] = "always loot",
                        ["jewelry"] = "always loot",
                        ["foodAndDrink"] = "never loot",
                        ["ornate"] = "always loot",
                        ["furnitureCraftingMaterials"] = "always loot",
                        ["tickets"] = "never loot",
                        ["craftingMaterials"] = "always loot",
                        ["containers"] = "always loot",
                        ["costumes"] = "never loot",
                        ["soulGems"] = "always loot",
                        ["runes"] = "always loot",
                        ["fishingBaits"] = "never loot",
                        ["ingredients"] = "always loot",
                        ["glyphs"] = "never loot",
                        ["styleMaterials"] = "always loot",
                        ["intricate"] = "always loot",
                        ["crystals"] = "always loot",
                        ["armors"] = "per quality threshold",
                        ["recipes"] = "always loot",
                        ["tools"] = "always loot",
                        ["poisons"] = "never loot",
                        ["weapons"] = "per quality threshold",
                    },
                    ["closeLootWindow"] = false,
                    ["version"] = 1,
                    ["minimumValue"] = 10,
                    ["enabled"] = true,
                    ["LibSavedVars"] = 
                    {
                        ["accountSavedVarsActive"] = true,
                    },
                },
            },
        },
    },
}