The "general consensus" on the forums is that, when you receive the max-out message, there might be some miniscule decimal level of improvement remaining. If you've got a guy at, say, 74.48 in a category, it will show as a 74 when you get the max e-mail and then trickle up to 74.51 or something, which would be enough to trigger a visual change to 75 for the guy.
It doesn't happen often, but it is one of those things that you'll see every once in a while in much the same way you'll see a kid occasionally lose a point after you've zeroed him out following receiving the max e-mail.