[lightspark]

Isn't it normal behaviour for any Get*Info function? I don't think GetQuestItemInfo is different from GetItemInfo. If item isn't cached yet, you'll get either incomplete data or a bunch of nils.

When you request info on not yet cached item, you need to register for GET_ITEM_INFO_RECEIVED event, after this event fires you need to request info again, but I'm not sure if GET_ITEM_INFO_RECEIVED fires after GetQuestItemInfo calls

Alternatively you may try to call stuff recursively w/ some delay if info is missing:

local function test_func(itemID)
    local _, link = GetItemInfo(itemID)
 
    if not link then
        return C_Timer.After(0.25, function() test_func(itemID) end)
    end
 
    -- do everything else here
end

Some checks to avoid infinite loops may be quite useful too