According to the PMBOK Guide, the project manager should manage stakeholder expectations and engagement throughout the project life cycle. The project manager should also support the product owner's decisions and authority regarding the product scope and releases. The product owner is responsible for maximizing the value of the product and ensuring that it meets the customer needs and expectations.
Therefore, the project manager should support the product owner's decision to launch the product with the MVP and seek better alignment with the marketing vice president in order to avoid this type of issue in the future. The project manager should also communicate the benefits and risks of the product launch and solicit feedback from the stakeholder. References: PMBOK Guide, 6th edition, pages 18, 37, 51-52, 286-287.