(NEXSTAR) – The Boeing executive in charge of the company’s 787 program commended an employee for coming forward and reporting an issue, according to an internal memo obtained by Business Insider and the Associated Press.

The issue turned up last month when a worker observed an “irregularity” in a required test of the wing-to-body join and reported it to his manager. When management investigated, they discovered several employees had not been performing required tests.

All the while, they were “recording the work as having been completed,” Scott Stocker, vice president and general manager of the Boeing 787 program and the South Carolina site leader, said.

“I wanted to personally thank and commend that teammate for doing the right thing,” Stocker wrote in the internal memo. “It’s critical that every one of us speak up when we see something that may not look right, or that needs attention.”

The memo was sent on April 29, Business Insider reported. Boeing did not return Nexstar’s request for comment.

The Federal Aviation Administration has since opened an investigation into falsified inspection records on certain 787 planes. Boeing said its engineers have determined that misconduct did not create “an immediate safety of flight issue.”

Boeing is taking “swift and serious corrective action with multiple teammates,” Stocker said.

No planes have been taken out of service, but having to perform the test out of order on planes will slow the delivery of jets still being built at the final assembly plant in North Charleston, South Carolina.

The company has been under intense pressure since a door plug blew out of a Boeing 737 Max during an Alaska Airlines flight in January, leaving a gaping hole in the plane. The accident halted progress that Boeing seemed to be making while recovering from two deadly crashes of Max jets in 2018 and 2019.

Those crashes in Indonesia and Ethiopia, which killed 346 people, are back in the spotlight, too. The families of some of the victims have pushed the Justice Department to revive a criminal fraud charge against the company by determining that Boeing’s continued lapses violated the terms of a 2021 deferred prosecution agreement.

In April, a Boeing whistleblower, Sam Salehpour, testified at a congressional hearing that the company had taken manufacturing shortcuts to turn out 787s as quickly as possible; his allegations were not directly related to those the company disclosed to the FAA last month. The company rejected Salehpour’s claims.

Two other whistleblowers have died in recent months. John Barnett, 62, was found dead in an apparent suicide in March. He had previously come forward about quality control and overworking concerns on Boeing’s production lines.

Joshua Dean, 45, died last week after being hospitalized with influenza and MRSA. He had raised concerns about 737 Max manufacturing defects at Spirit AeroSystems, a Boeing supplier.

The Associated Press contributed to this report.