Facebook may send you unwanted texts if you use its two-factor authentication (UPDATE)0
So I signed up for 2 factor auth on Facebook and they used it as an opportunity to spam me notifications. Then they posted my replies on my wall. pic.twitter.com/Fy44b07wNg— Gabriel Lewis (@Gabriel__Lewis) February 12, 2018
We've reached out to Facebook for comment on the case, but we've received no response yet, so we're not sure if the unwanted texts people have been getting are a feature or a bug.
If you'd like to avoid receiving text messages you can use some of the other methods for two-factor authentication, including receiving a code from Facebook's Code Generator, using a third-party app or approving your login from an already recognized device.
UPDATE: We've received Facebook's response regarding the case:
source: @Gabriel_Lewis via The Verge; Facebook