For some reason, when you repair weapons to a 100%, you can't use that weapon to repair any other damaged weapons. Also some of the cap values are off, when you're at 100%. A good example is the laser rifle, which has 2 different cap values when repaired to 100%.

If a weapon is at 100% you can't repair anything or use it to repair anything. Why would that be abnormal? Not sure what your 2nd question means. Does that mean if you are carrying 2 laser rifles at 100% they have a different value?

The problem is you can't use a 100% repaired weapon to repair another weapon. The problem is that cap values that they would sell for at 100% are different, at least it is for laser rifles.