I'm assuming that you cut your own holes, as most concentric knockouts won't go to 3 or 4 inch sizes. As has been mentioned already, the base of the issue is the conduit not bent right. Either remove, fix, and replace the conduit, or try to convince the inspector to let you use ground bushings instead. At this point he may just have you fix the conduit. You should be relieved it's not for the Army Corp of Engineers, they'll walk around with a level and protractor. If it ain't right - you get to go back and do it again. And don't blame everything else in the world on the problem to the inspector. If YOU ran the conduit and YOU underbent the 90, than it's NO ONE elses fault that particular part of the inspection failed. So fix it. Now. Then report to your nearest can of beer and have a good laugh about it.