Duplicate detection

As funny an it sounds, It seems like the duplicate detection is not active or it times out gradually.

We have set it up to detect by phone number. But when I am in a record that an existing customer with the same phone number has just created, I do not see the duplicate warning.

I find myself frequntly going back to the set up and change the customer duplicate detection criteria to something else in the list, save it, then back again and set it back to phone number to make it work again.

After doing this, The record shows the warning.