Translation:Do you want an apple or an orange? No thanks.
It should accept both "Do you want an apple or an orange? No thanks" and "Do you want apple or orange? No thanks". Did you actually try it?
The course teams cannot do anything about possible system bugs. If you think that Duo has a bug, please send a bug report - https://support.duolingo.com/hc/en-us/articles/204728264-How-do-I-report-a-bug-