The aircraft carrier Ronald Reagan’s annual spring patrol out of Japan was delayed last month due to a “material issue” with the ship, 7th Fleet officials confirmed this week.

While the Navy refused to specify what types of issues the Reagan faced, they arose during recent sea trials and required in-port repairs, command spokesman Lt. Paul Newell said in an email.

The carrier, based out of Japan, had undergone extensive maintenance, and the sea trials tested the ship’s systems and equipment, according to a Navy release from last month.

Sea trial exercises involved high-speed turns, sea and anchor evolutions, precision anchoring trials and testing of self-defense systems.

The Reagan returned from sea trials on May 11, and the ship deployed early this week, according to the service.

While the trials revealed the material issue that delayed the Reagan and its strike group from deploying, its commanding officer, Capt. Buzz Donnelly, said in a Navy release that the ship “performed remarkably well” during the trials.

“The crew’s training and preparation was a primary factor during all the evolutions,” Donnelly said. “They should feel very good about the fact that they came in well-prepared and executed as well as they did.”