Why is the minimum value for "business days" equal to one when reporting trips for the foreign earned income exclusion?

I am claiming the foreign earned income exclusion, but I traveled in the US for a week or so on vacation. When I report this trip during the interview, I have to enter a value for "business days" in the US. Since, I was not in the US on business, I would like to enter 0. However, TurboTax gives an error and says the minimum value for business days is 1. Is it possible to avoid this error? Last year, I was able to enter "0" for business days without this problem.