When I have created a Full Stack Triggered Experience in Sitecore Personalise that is using a Decision Model. The Full Stack Triggered Experience is failing when it is triggered with the error NO DECISION in the execution report.
When a triggered full stack experience/experiment is using a decision model, the decision model must return an offer. If an offer is not returned from the decision model connected to your the full stack triggered experience will fail with the error NO_DECISION.
To avoid the NO_DECISION error, return any offer from your decision model. This can be a dummy offer that is not used in your full stack triggered experience.
This is not the case for Full Stack Interactive experiences/experiments or Web experiences/experiments. For Full Stack Interactive or Web experiences a decision model can be used that is not returning an offer.