Can a contact to enter a program more than once and how to setup properly

Hi Eloqua fellows,

I made a simple Eloqua program with the listener step looking for a change in a contact field named "Email Permission", then we use Salesforce Integration App to send them to SFDC depend on a contact field indicating their countries and states.

We expected a single contact to enter the program more than one time however, we tried multiple test and a contact can only enter the program once.

Surprisingly, there was a similar program from a team in different country using the same Eloqua instance with us that a single contact can enter multiple time. We tried to discuss together but cannot find out the reason why one program can and one couldn't.