On the exercise screen itself, instead of "Do you have a moment for me?", Duolingo shows as the correct answer "Do you have a 2nd for me?" Clearly, this is an error. Not all "seconds" are created equal. I assume it means "second" (as in a unit of time) as opposed to "second" (as in the ordinal number, which can also be written "2nd").
Duolingo's stupid algorithm for numerals disagrees with you: it thinks all "seconds" are created equal. Just like all "ones", which is how you can end up with ridiculous things such as "no 1" for "no one".
You can file a bug report about here, if you like: https://support.duolingo.com/hc/en-us/requests/new