Alpha hairs are made with something called the "SimGlass Shader" that is coded by EA and they use it in transparent clothes. The shader was not designed to work with hairs although it is what people use to give it transparency. As EA never intended it to be something that hairs would use they did not added compatibility with a lot of things. One among those is water.
Alpha hairs have not been compatible with water since the beginning, but it is more apparent now that Island Living came out. Unfortunately the shader is hard coded in the game engine and it's not an easy fix to resolve this issue.
Please do not PM me to help you with your creating problems. You can post in the Creators Help so everyone can see the problem and solution.
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