Ha! I thought the same thing and looked up the definition and "one", unlike "three", has meanings which are not related to the number:
https://dictionary.cambridge.org/us/dictionary/english/moment
I guess they didn't want to spend the ten minutes it would take Alex and Andy to have an unskippable grammar nerd cutscene!
I'm actually not sure if I would've called or not to be honest. I guess I'm hindsight the wording of the task would have needed to be more precise ("say anything that can be interpreted as a number").