Homeowner here: was told my water heaters are piped incorrectly

As the title states: I was just told my water heaters are piped incorrectly, they’ve been this way for 10-15, Maybe 20 years lol

I have no idea, so I’m completely shocked hearing this. It is likely that they’ve been installed wrong or is this potentially an older way of doing it? Not too sure, I appreciate any feedback

“See your pipes the cold water is coming in one of them then it's coming out hot to the second one then it's coming out hot from the third

Yeah, you basically heating water for the first one then you reheat it for the second one”