Torani Syrups

I’m really hoping someone here can help me out with this, or explain if I’m doing something wrong, or if this is common.
Every time I steam a torani fruit-flavored syrup, strawberry, cherry, sugar free black cherry, etc., in dairy milk it starts to curdle. ONLY with Torani, I don’t have this issue with Monin (my preferred, but where I order from just sends whatever brand in that flavor). Am I doing this? Is there something I can do about it? I’m just a little lost and wanted to do a chocolate strawberry latte for a Valentines Day special, but like I said, I can’t always guarantee Monin syrups. Any help would be great appreciated. 🫶🏼