I am setting up a suggested lookup filter on the Contacts of a New Case Entry page layout.
The problem seems to be that only results from "Recently viewed Contacts" is returned (in the screen you can see: 
While the actual account has 11.
OFC - if I click on any of the accounts contacts [that are NOT shwon in the list] and I go to the Lookup filter again - I will see that last contact added to the list
sample of doing that with a 7th contact on the account.
- I am sure that's not the way to go.
On the Search Settings - I have disabled the checkbox: Use Recently ....
But that didn't change the results.
- Lookup search not returning results - Did not solve my issue.
I am using the Standard Page - not a VF one - and don't plan to create a VF look for this
I get the same behavior from "New Case page" and "Edit Case Page"