Team is a custom, single-select picker field that can be added to an issue in Jira using the type key com.atlassian.teams:rm-teams-custom-field-team. As per Linking ProForma fields to Jira fields documentation, a few Jira fields can't be linked to Form fields. Team is one of the unsupported fields.

Suggestion:

Add the ability to link Team and other unsupported fields to the Form fields.