Hi mumma! Are you trying the gradual change too? My baby changed FM twice because she couldn’t poop but she didn’t have diarrhoea when changing. I used this type of chart.
Perhaps try to give it a few more days to let him get used to it as PD suggests. But I always follow my instincts as well so if you feel it’s something wrong, change the fm 😄♥️ all the best mumma!