Labradora
False.
I still take a flask of tea with milk in it out on my favourite bike ride and drink the tea while taking my mid-ride rest on a park bench.
OH and I have taken tea and coffee flasks on longer journeys and found them still drinkable at the end of long days'travelling.
Degree of warmth might be a problem , but not curdling.
I wasn't suggesting curdling, but boiled milk tastes differently to fresh unheated milk.
I once made the mistake of reheating a cup of tea with milk in it in the microwave. It had exactly the same effect as making up tea with milk and then keeping it hot for hours in a flask. It tasted quite unpleasant, but it wasn't curdled or 'off' in anyway


