The particular form of the description at issue can be interpreted (arguably, is most naturally interpreted) to direct a different outcome than is usually expected from FizzBuzz, to wit, it directs that on numbers divisible by 15 "Fizz", "Buzz", and "FizzBuzz" all should be printed, rather than just the last.
The description is underspecified, no surprise there, but that's different from claiming it's incorrect. As far as its purpose as an interview question goes noticing this interpretation would probably be seen as a good sign.
If it can be satisfied in a way that is materially different from what was intended, then it is both under-specified and incorrect. This is a not-uncommon source of errors.
Natural language can be used with precision, and this is an important skill for engineers. Being able to identify ambiguity and inconsistency is an important part of that skill so yes, noticing it within a question should count in favor of the candidate. Dismissing it as being pedantic is the wrong response, because if you are working on something critical (secure communications software, for example) you need to handle ideas with precision.
