The modern One Piece English dub was always infamously far behind the Japanese episode releases. That's because Funimation, now part of Crunchyroll, didn't begin working on the series until 2004. But the One Piece anime started in 1999. That five-year gap between the English dub and the Japanese subs remained the standard for a long time.
Source:https://www.cbr.com/one-piece-dub-catching-up-to-sub/