AutoMapper's Ignore() not working when using ForSourceMember?

Change the mapping to use ForMember:

map.ForMember(s => s.DateCreated, opt => opt.Ignore());
map.ForMember(s => s.DateUpdated, opt => opt.Ignore());

If the property that you want to ignore only exists in the source object then you can you MemberList.Source in combination with the option method DoNotValidate(). See below:

CreateMap<IArticle, Article>(MemberList.Source)
    map.ForSourceMember(src => src.DateCreated, opt=> opt.DoNotValidate());
    map.ForSourceMember(src => src.DateUpdated, opt => opt.DoNotValidate());

This is perfect if you are using AssertConfigurationIsValid and want to ignore validation of certain source properties.