According to Bloomberg, two IT contract staff made changes to the live NOTAMS database, causing the data to become corrupted. They made these changes, without following standard practice procedures.
Parts of the NOTAMS system are said to be 30 years old.
FAA Computer Failure Caused by People Who Damaged Data File – Bloomberg
It seems nothing has changed regarding the FAA and information systems – in decades. I wrote my senior thesis in computer science on the use of automation in the air traffic control system, way back in about 1980. The FAA was always behind the power curve on IT systems design and implementation.