My daughter drinking this now. No issues.
But I do notice that the milk powder is thicker and requires hotter water or more mixing before it can be dissolved.
Oooh, hmm do you still have stage 1? What you can do is to go back to stage 1 for a day or two and see if the poo goes back to normal? It's okay to feed stage 1 because a PD told me you can feed stage 1 all the way till 12 months. Just that have to feed more iron-rich food for solids.
My kid is taking the ready to drink step 3 and so far no issues!
Fitrina Lim