I found the same thing. I tried my boys on the dry several years ago and found it gave them the smelliest poos! So I never used it again. I tried Jaffa on the wet food more recently and it gave him diarrheoa. I'd try a different food that's comparable unless you're happy living with stinky poos!. Is it the dry food you're feeding? If so you could try Royal Canin or James Wellbeloved.
edit - just realised that you're talking about presciption diet and I'm talking about science diet
I have tried Jaffa on Hills t/d and that upset his tummy a bit too. Royal canin do prescription diets so whatever one you're using perhaps see if there's a Royal canin one you can try?