When setting up a new portfolio plan over 4 different teams (projects), I've created a new cross-project release and added some epics for each team which are needed for this release. Now, the teams can add stories during refinement and so on.
When I took a look at the scope of this plan a week later, I suddenly see new epics and stories in the scope of this plan. I see no link to releases, initiatives or anything else, other than these are created in the projects of the teams in this plan. Is there any way to prevent this?