3 month old’s poop

My 3 month old combination fed baby recently begin pooping only once in 3-4 days. When he does poop, it is mustard, runny and soaks the whole diaper (refer to pic). He has been drinking less as compared to when he was 1-2 months old but still clocks 500-600ml or more each day. He would however fuss/cry during feeds/refuse the bottle at times. He has always been quite bloated. He is otherwise a happy baby and gaining weight. Are these normal?