Those are not 'good' details... but, as writen "minor" imperfections. What kind? Well, all I read in your post is all I know: these are not surface graining (otherwise this would be expressely mentioned) so some kind of "polish lines" come to mind. There has been a post about them a month or so ago. Pits or other natural caracteristics which would not influence clarity (otherwise would not be mentioned at the "cut" chapter) are also possible. Some of these could be corrected by repolishing, sme not. If the diamond is of high grade otherwise (as I remember you were after) i'd imagine that whatever the caracteristic was, it did give the cutter a hard time or else it would have been treated in the first place.
After all, no cut characteristics mean a FL grade.