User blog comment:Fliu/Chapter 956 Thoughts/@comment-30887974-20190919181532/@comment-1890236-20190919211150

It's not a typo.

In the panel where Koby is reintroduced, it says...

海軍本部少将兼「SWORD」隊員コビー. In other words, "Marine Headquarters Rear Admiral, SWORD member, Koby.

I don't know if it's a mistake or intentional. As was mentioned below, maybe he got promoted during the Levely due to his actions.