What happens when someone goes over the 8 mg RDA of iron consistently ?
Excess iron can be harmful. This trial was even stopped early:
https://www.sciencedirect.com/science/article/abs/pii/S0140673606679622
Granted, we don’t know if it was the iron or folic acid at fault, but it’s not the only experiment in which extra iron was detrimental.
It is not a scientific study, but this article links to several studies to look at some of the possible long term risks associated with high iron intake. It could be pretty scary.