Recently, a Lion Air 737 MAX crashing into the sea after departing Jakarta, this lead to the investigation of to why it happened. It has been discovered that incorrect readings from a flight monitoring system may cause the plane to suddenly began a nose dive, this is what investigators believe happened to the Lion Air flight. Boeing will be releasing a warning to all 737 MAX operators about this issue.
Heres a great video by Dj’s Aviation explaining it: https://www.youtube.com/watch?v=g-CK8AD_kjM (goes more in depth)
Article from Bloomberg about this issue: https://www.bloomberg.com/news/articles/2018-11-07/boeing-is-said-close-to-issuing-safety-bulletin-on-737-max-jets