During the last couple of months, M2E team has been monitoring updates of the new managed payment regulations. According to eBay, the enrollment into the Managed Payments program will happen gradually.
M2E development team has been closely reviewing the related API announcements and release notes. The developers confirmed that the seller's enrollment into the new eBay managed payment will not affect any listings within M2E Pro. For now, you can just ignore the warning notices.In the future M2E Pro version, 'Managed Payments' option will also become available among the other methods in the Payment Policy.
M2E Team will continue observing the situation to ensure M2E Pro compatibility with the channel changes.