I set up a live plan which is sourced from two JIRA boards. At the time of import, some issues I import are resolved (status "Accepted" in my screenshot).
Unlike other issues, these ones are not assigned a Team.
This behavior partially voids the use of the team filter, which now only helps selecting items that were resolved AFTER the plan was created, but not those resolved BEFORE.

It would be then very helpful if these stories were equally assigned a team (at plan creation). The team (or teams) could be set based on the issue source, as a source is normally associated to one or more teams.