Normal or not????

We had a suspected intolerance for my little boy . His symptoms was constipation along with pther symptoms (not mucus poo). We reintroduced formula , everything has been fine , he has been on it since around the end of May but his poo seems to be stringy / mucusy? What’s the likelihood of this showing up now do you think ? I’m also thinking maybe his tummy is just abit upset because he’s putting EVERYTHING in his mouth ! No other symptoms as of yet . Reflux is being managed Just to add his symptoms never really went on nutramigen just his poo was better.