I would recommend pointing out errors one on one, not in a meeting of a manager's direct reports.

In this one on one, I would feign having trouble understanding the model and ask the manager to walk you through it in more detail so you can understand it. During the review, ask some pointed questions that will lead the manager towards the error.

In many cases while explaining the model in detail, the manager will discover the error on their own.

This approach allows the manager to save face. Many times, the manager will be very relieved and many times they will realize you knew there was an error all along.