While other fast casual chains struggle with closures and bankruptcies, the company reports growing revenue and margins.

Contemplate existence while the red peppers roast ... Toss in the sun-dried tomatoes, chipotle peppers, garlic. Add the broth. Kick the heat to high, get it to a boil, and then drop it down ...

It's not hard to believe that Chipotle would catch Buffett's eye based on its brand, customer focus, and pricing power. But there's one major red flag that would likely cause him to hesitate.