When using dynamic membership in Microsoft Teams, it is indeed true that the membership of a team is primarily governed by dynamic rules defined in Microsoft Entra ID. However, there are specific nuances regarding ownership that you have encountered.
According to the context, while dynamic membership rules dictate who can be a member of the team, they do not apply to team owners. This means that owners can be added manually through the Microsoft Teams Admin Portal without needing to qualify for the dynamic membership rules. Once added, these owners will not be automatically removed by the dynamic rules, even if they do not meet the criteria set for dynamic membership.
Therefore, your observation that the two owners remain listed as owners of the team despite not qualifying for the dynamic access rules is indeed working as intended. Owners can be added independently of the dynamic membership rules, and their status will persist unless manually changed by an administrator.
References: