Good day everyone My baby turned one recently and we switched to NAN …

Good day everyone My baby turned one recently and we switched to NAN 3 from 1 year old, previously giving NAN 2 from 6 months to 1 year old. Since starting 3, the child's stool has changed, very hard, like Play-Doh, I think maybe because of the switch to 3????? Has anyone had this? I give him an apple every day, prepare a special soup for him at lunch with minced meat and carrots. But I don't think it's because of that, as I have been giving him soup before too.