Selling Graphic Design With Proper Measure And Being Clear About What's Missing
You can give a disclaimer to the client at the time of accepting the project that since the design is open-ended and you will resolve all the signifanct issues with the design and will try to resolve all the minor issues as well but there is still a slight chance ( although very unlikely ) that end user might encounter some minor issues. Additionally you can also choose to offer after sale service in cases where a minor issue is reported by the end user.