Can I just check here?
Many years ago, I used to take milk in my tea and coffee. And, well before it became cold, the milk scum would form, and the texture of the drink became pretty disgusting. Indeed, I used to drink it too hot in order to avoid that!
That was a part of the reason I gave up milk in hot drinks. And, once I had done so, I realised how much nicer they were without (assuming good choices of the actual tea or coffee).
Does anyone use an Ember, or a Burnout, and take milk? Does the drink really stay acceptable?