Yes, folic acid in supplement form is one to beware of taking as a supplement. Folic acid and natural folate aren't the same. Our bodies use folate and it's hard for some people to convert folic acid to folate. When we can't make the conversion, free folic acid ends up in tissues.

Some scientists think folic acid disrupts the action of natural folates from food. As you say, best to get it from natural food sources like leafy greens. Some packaged foods are fortified with folic acid , which is a concern for people who eat a lot of these foods. Excellent article!