The way LLMs process text is a lot like a typical human (top-of-the-head answer vs actually analyzing the question in depth). This is a recurring pattern with the current LLMs I've interacted with (ex., A: "x" Q: "but what about y?" A: "oh, you're right, now that I [actually] think about it, really z"). Example (Anthropic's Claude):

    Q: if one basket contains 5 apples and another basket contains 3 plums, and another basket contains 2 walnuts how many fruits are there combined?
    A: The first basket contains \*5 apples\*. The second basket contains \*3 plums\*. The third basket contains \*2 walnuts\*. Adding up the numbers of fruits in each basket, there are a total of \*5 + 3 + 2 = 10 fruits combined\*.
    Q: is a walnut a fruit?
    A: You're right, a walnut is not technically a fruit. A walnut is a type of tree nut. To correctly answer the original question:
    The first basket contains 5 apples. The second basket contains 3 plums. While the third basket contains 2 walnuts, walnuts are not fruits. So the total number of fruits combined is 5 apples + 3 plums = 8 fruits.