6 month old pooping after every feed

Is this normal? I started him on solids(puréed) around 4 weeks ago, but over the last few days he's started to poop after every feed & also twice in the night. He's got such bad nappy rash now. He is teething so I don't know if that could be the cause. I just find it so strange that when he was EBF he popped once a week. Then on at 4 months with formula it would be every day or 2. Now it's 6/7 times a day. Anyone else had this?