[Meta] Decreasing User Retention After Sign-Ups

Problem#

On Facebook, a new sign-up flow is launched, requiring more profile information. AB test results show that the percentage of people that add more profile information increased by 10%. However, the 7-day retention decreased by 4%. 

1. How would you investigate the sign-up and engagement metrics moving in opposite directions?
2. What is your recommendation to the product manager...