It doesn’t sound good. If they optimize their training for a particular pool depth and get a different depth, some can be more thrown off than others. Why isn’t this standardized?
There was a story about former NBA player Bill Bradley (yeah I’m old). Seems he was missing more free throws than usual during a practice in a new gym. He stopped throwing, paused for some moments, said to the coach “hey you know what? That basket is about an inch too high”. Adjusted his throw to deal with that and shot about as good as normal afterwards. Nobody believed him about the basket but someone got a tape measure and he was almost exactly right (off by 1/8" iirc). This is in John McPhee’s profile of him, “A Sense of Where You Are”.
The swimming pool thing sounds sort of similar. Try some web searches on Ken Ono and swimmng. Wnat to know why so many Olympic team members are from the U. of Virginia? Because Ken Ono is a professor there. Of algebraic number theory. I kid you not.