Summary

Advanced Roadmaps only allows to set one team on an issue; whenever you set a team on an issue with children, that team will be set on all children and any other previously set team will be overwritten in Portfolio, and once that change got committed back to Jira, also in Jira.

If you set different teams on child issues of an issue that itself does not have a team set (e.g., set two different teams on the child epics of an initiative), the parent will show both teams as an aggregate of the teams set on its children (hence the blue background that indicates these values are not actually set on the parent) but actually still has no team set. If you try to set a team now, it will be set on the parent and set the same team on all children. It is not possible to set multiple teams on an issue

This suggestion proposes to relax this limitation and allow setting multiple teams on issues.