Detect artifact

Not sure if this should go here or to the Gameplay board but here it is. Does detect artifact fire on 'not yours' sleek spots? Non-sleek spots? My experience being it goes off 10 times out of 10 on 'your' spot and 0 out of 50 on 100% confirmed 'not yours' sleek spot. Thus if you come across a legit sleek spot - you'll never know you found one(via detect artifact). Is this the way it's supposed to work? Thanks in advance