I have the same issue you had with Champion Challenger. It seems you can't use a Program within the Engagement stream. You have to use the individual emails in order to use the Champion Challenger functionality. It didn't work initially but then I tested it with just the email itself in the stream and it worked. But nowhere does it say that it wouldn't work in the documentation. I opened a ticket with Support.
If you're using programs in engagement streams I can only imagine the complexity to properly champion challenger for Marketo. It would be wonderful to have, but hard to build out for them.
Looks like we will need to do our reporting outside the "out of box" functionality of champion challenger.
Im always in favor for more robust documentation. Marketo cant do it all though right?
Post your support update, be curious to hear what they say.
Well it seems pretty straightforward. I created a Smart Campaign that sends the email within the program as instructed in the product docs when you want to use Programs instead of individual emails in Engagement Programs. When I export the report of the Champion/Challenger it shows that all the emails were sent for the Champion. It literally skipped the challengers. I would think in the back end programming of Marketo they could easily fix this with some type of command in the code to split the list into the various percentages as specified in the Champion Challenger.
I guess another alternative if I wanted to use Programs within Engagement Programs would be in the Flow to do a Random sample 50 percent and have it send the two emails. Reporting-wise it would be more manual but I would see the two subject lines in the report. Then I could track how it is performing an manually remove one of the emails. Not as easy as just "declaring a winner" but a workaround nonetheless.
I think it was an oversight on their part when they created Champion/Challenger. The documentation says clearly: "Champion/Challenger emails only work with trigger campaigns and engagement programs. For batch mailings, use the email program's A/B testing functionality."