If your iPhone X has Face ID issues, Apple might have a solution
If your iPhone X has Face ID issues, this is Apple's new repair process
If your iPhone X has Face ID issues, Apple is likely to repair the rear camera module or offer a free replacement unit for you.
According to a new support document sent by Apple to its retail stores and Authorized Service Providers, Genius Bar employees are advised to run a diagnostic test to see if the Face ID issues could be resolved with a rear camera repair. If it cannot be resolved, the customer is offered a free replacement unit.
It seems a little odd that Face ID issues could be addressed by repairing the rear camera, but actual customer accounts appear to confirm the relationship. One customer claimed to have been told by a Genius Bar employee that the TrueDepth camera - which powers Face ID - and telephoto camera lens are connected.