Poop question 💩

Our son is a great pooper. 3-4 times a day and normally it is a mush to soft soild everytime. However, the past 2 weeks he has had a poop a day that is firm little balls that stick to him in matter of seconds. Like literally he started pooping I stood there until he was done and changed him and these things were like velcroed to him. The app says little balls is a sign of constipation... but he seems to still be going and the next poop may be mush. He is eating the same varity of foods he has been for a bit now. And it does not seem to corralate with the foods. Any thoughts? Should I be concerned? Thanks.