I'm guessing that maybe the threads are stripped out on the windage screw or the aperature, hard to say without looking it over. One thing you could do is take the rear sight apart and inspect the components. It comes apart pretty easily. Or you could go and buy a fold down BUIS that would fit under your scope just in case something happens to your optic you would have something for back-up.
To check to see if your front sight base is cocked to one side or another is to turn your barreled upper upside down and rest the two ears of the front sight base on a flat surface then lay the top picatinny rail of the receiver on a block that is parallel to the same flat surface (a table saw works well for this) that the front sight is sitting on. If you don't have a table saw, the kitchen counter will work as well but may not be as flat as the table saw or maybe you got a buddy with granite countertops. This is not really precise but will give you an idea if your front sight is fairly close to being perpendicular to the picatinny rail on the top of the receiver.
If the ears on the front sight are both touching the flat surface, the picatinny rail should be laying flat on the block. This would indicate the front sight was perpendicular to the flat of the picatinny rail. If the rail doesn't lay flat on the block then your front sight base is not perpendicular to the rail.
