Airbus is bracing for slower-than-expected September deliveries after discovering a coating defect affecting its best-selling A321neo jets. About 500 aircraft are involved, including 250 at various production stages, and a cumulative 20 A321neo deliveries have been pushed into the fourth quarter partly because of the quality problem. The defect affects protective primer on forward-fuselage stringers and does not affect safety. Several airlines continue to accept affected aircraft, with repairs required within two years and expected to take up to nine days. Airbus and Leonardo are investigating the cause at TESI, a Leonardo subcontractor south of Naples. Airbus declined to comment on incomplete monthly delivery figures but said there had been no change to its full-year targets, including its 2026 delivery target.