Boeing has identified a previously undisclosed software problem that could affect an automated navigation feature on some 737 MAX aircraft.
The issue can occur when pilots change their planned flight path after a missed approach.
Boeing said it informed operators about the problem last month.
The company said pilots retain procedures for safely handling the situation.
Boeing is working on a permanent software update.
The Federal Aviation Administration said it is aware of the issue.
The FAA said it would review the matter and take action if a safety concern is identified.
