Sounds like something potentially related to you rather than the Kryptonite locks. Any chance you park the bike under trees that shed somehow resin? You might then hear though about similar experiences of other students. Is your bag dusty, with dust gradually filling the inside of the lock? I once immobilized my lock by spraying dry graphite into it, which I thought would lube the lock well. Instead, the lock virtually froze. I rescued it by spraying next lots of light oil in. You might try the light oil when your lock jams. Something about the manner you turn the key, either not finishing or overdoing it, or turning under strain?