I ran into this situation during the setup and testing of a demo. I had a contact list and a marketing automation plan where a contact can be enrolled multiple times. I used the option to enroll contacts from a list to start the scenario and used this list over and over again. Very happy by the way, that with Siteore 9.1 these options are finally available now!
The first listener that I used was to check if the contact had opened an email. The first time I enrolled the list everything worked fine. But the next times each contact directly passed the listener and followed the yes path. At first I did not understand what was going wrong and wondered if there was a bug that slipped into 9.1.
But then it hit me. The interactions and events of each contact were stored for each contact in the Experience Database. So the email open event was already registered. And because I used the same contacts for each test run with the same emails, the marketing automation engine immediately evaluated the email opened listener as ‘yes’ as this was the data stored in the xDB.
So, that brings me to this weeks tip. If you are using the multiple enrollment option, make sure you design your marketing automation campaigns in a safe way, were you are absolutely sure that listeners that need to evaluate each time, they actually do so. Take some time to think and test properly.