FindPartsInRegion3WithIgnoreList not finding other parts?

Hey! Yes,you, I'm sure you know about Region3 :) Let's get to the point - I'm trying to detect a player in a region3 {BossArea}, resorting to IgnoreList cause I dunno how to get the player with WhiteList and I don't want the computer to do lots of calculation thing with the regular FindPartsInRegion3. IgnoreList ignores the boss and the map. vvv

local p0 = script.Parent.Region3Marker.p0
local p1 = script.Parent.Region3Marker.p1
local BossArea = Region3.new(p0.Position,p1.Position)

BossActive = false
local Torso



while true do
    print("test")
    local checkHumanoid = workspace:FindPartsInRegion3WithIgnoreList(BossArea,{
                        workspace.Boss.Cave,
                        workspace.Boss.bigman},10000)
    print(checkHumanoid)
    for i,parts in pairs(checkHumanoid) do
        print(parts)
        if parts.Parent:FindFirstChild("Humanoid") then
            print("INITIATE!")
            end
    end 
    wait(3)
    end 

The problem is, print(checkHumanoid) works fine, while print(parts) doesn't get printed. I watched a tutorial regarding Region3 andfor i,part in pairs(Region3) do is what is used. However, the script seem to stop at print(checkHumanoid), so after a while i get a print output like this:

  test
  table: 0x1787964970b079a4
  test
  table: 0x643d5921b5633ea4
  test
  table: 0x5bd54eea6da03824

How would you fix this?