When triggering a rollback users can get exception if the plan definition has changed. For instance here's an example from a customer:

In my build plan, I was collecting to sets of artifacts. Let's call them "artfacts1" and "artifacts2". I created a build called "build-1", and these artifacts were archived with that build.

I created a deployment plan, and it referenced both "artifacts1" and "artifacts2". I created a release called "release-1" and deployed them.

Later, I decided to remove "artifacts2" from my build plan because moving forward I don't need them.

Now I realize I need to rollback/redeploy my existing deployment using "release-1". If I try to do this, I get:
"Could not execute 'ENVIRONMENT:6258689': java.lang.RuntimeException: java.lang.IllegalArgumentException: Unable to find an artifact definition for name: artifacts2"

We should not trigger that exception and should have an appropriate message informing the user that an artifact definition is missing to replay the plan.