Incorrect texture when swimming in water in old worlds

When playing in my old world from minecraft beta 1.8.1 in minecraft snapshot 13w25c - 13w26a , I found that when I was swimming in the river, the water texture for swimming is wrong .It happened in both single and multiplayer. Overview of water is okay, but when go into it ,it become white in colour .It won't happen in minecraft 1.5.2 . I'm annoyed with this bug , please kindly solve this problem thanks~.