I have had problems with a quick release chuck after frequent use (or storing) of magnetized bits in them. The little ball bearings (which my version use as the locking mechanism) would get magnetized and not move as they should. I found while holding the release collar back that blowing compressed air down the shaft of the bit and/or diligent fiddling (all while holding the collar in the release position) would finally do the trick. I keep a set of bits that I never use with magnetic holders in an old Altoids tin (just to keep them separated, there's nothing special about the tin) and haven't had the problem since. YMMV.
Any sufficiently advanced technology is indistinguishable from magic.
- Arthur C. Clarke