no, 'mi havas' is correctly used for both English examples you gave. 'i have' or 'i am having'. the 1st is simple present tense. the 2nd is continuous present tense. both are correct. but sometimes DuoLingo just doesn't have all the correct options entered in its database yet. that why the user feedback feature is so important for them to fix the many shortcomings that course translators just could not realistically be expected to enter all the possible options for every answer til they are reported by us users.