I've built quite a few engagement programs without too many issues, but I haven't used a list import for any of them until recently (we've always just used the criteria in our smart list via a 'add to nurture' smart campaign to pull people from our CRM).
In this case, we added the list asset and in our 'add to nurture' smart campaign, set up a 'member of list' filter and a few others, because we knew we were going to need to weed some people out of the list we uploaded. Everything in my schedule tab and the 'set leads to be affected' looked correct, and the overall number was smaller than my initial list upload because of the filters, which was intended.
After the first cast it became apparent several people had been emailed who should not have been. Looking at some of our reports, it looked like the number of total emails delivered was a lot higher than what my smart campaign had said was going to run - right around the same number of people in my initial list upload, so as if I had never set any filters to block anyone. Looking at the program level, the total number of members matched the unexpected number of emails that had been delivered (not something we would have normally checked, as we relied on the smart campaign to tell us how many people were going to be added as members, and we shouldn't have had any members until the smart campaign had ran in the first place).
After digging around, what we think happened was after importing the list and setting the acquisition program as that program (because these were 'new to marketo' leads), these people were automatically added as members and immediately added to the first stream. Because we didn't realize this had happened, my smart campaign ran, and because the entire list had become members and added to the stream, they received the first cast, leaving the smart campaign ineffective.
Because I haven't used a list import in this fashion before, and because I can't find any documentation on it, I wanted to reach out to see if anyone else has experienced this. We tested the whole scenario with an engagement program and list upload again, but set acquisition program as 'none' and members were not automatically added. We tested it again by setting the acquisition program to the actual program, and leads were automatically added, so this seems to be the trigger?
Is this normal list import behavior? Everything I've been taught in regards to an engagement program is that you set program membership and stream assignment in a smart campaign via a flow step, so this was surprising.
Open to any questions or comments. I know what to look for next time at least, it's just unfortunate we had to learn it the hard way, and for something that isn't very intuitive.