The FAA is concerned with lavatories "becoming detached" 

The Federal Aviation Administration (FAA) has issued a proposal for a new Airworthiness Directive (AD) aimed at addressing corrosion issues found in the lavatories of certain Boeing 787 aircraft models, including the 787-8, 787-9, and 787-10 variants. The corrosion has been detected in the lower fitting assemblies of some lavatories, raising concerns about the safety of passengers and crew.

More - Federal Aviation Administration Calls for Immediate Action on Boeing 787 Lavatories to Address Corrosion and Ensure Secure Flight Operations: You Need to Know