I don't remember having this issue in the past. For whatever reason, when I run the calculation wizard to generate my ground texture mask and satellite map, I can't get beach sand to stop at the correct altitude.
It was placing sand about 10-20m above sea level by default. So I started tinkering with numbers, and I got sand to meet exactly at sea level, but I just want it about 2m above sea level and no matter what I change it doesn't seem to make a difference.