Help!

I cannot for the life of me remember how to keep this from happening!

We use Monin syrup, and for some reason some of the fruit flavors do weird things with milk. Such as the cherry - this was supposed to be a cherry almond steamer. The cherry… seperates the milk? It seems to almost curdle the dairy - leaving it chunky and on top, and then water on the bottom. I seperated it into two cups so you could see it. Anyone have some tips?

I steamed it with the milk, and then I tried stirring flavor into steamed milk after it was hot. Heeeelp.