Hello everyone! Girls, my son is constantly spitting up? We're on mixe…

Hello everyone! Girls, my son is constantly spitting up? We're on mixed feeding, I'm supplementing with Nutrilon Pepti due to allergy. He spits up mainly after clear liquid mixture. It can happen immediately after feeding, or even 1.5 hours later. For example, yesterday I fed him before going for a walk, held him upright, put him in the stroller - he spit up like water, I changed his clothes twice and we went for a walk ? an hour later in the stroller he spit up ? two hours later at home he spit up ? basically constantly. After breastfeeding too, he spits up but not as much, just a little bit. The baby is active and cheerful. Has anyone had this?