Question:
I accidently heated soup that was made on dairy utensils (as per label with no obvious dairy ingredients) in a meat pot. Do I need to kasher the pot?
Answer:
The pot does not need to be kashered, since any dairy that might have gotten to the pot was taste that was absorbed and then reabsorbed (nat bar nat bar nat), since the taste went from the dairy into the equipment, then from the equipment to the next product, and then from there to the meaty pot.
Sources:
Tosefos Avoda Zara 71a D:H Bas Yoma, Shach Y:D 94-15
