In an extremely small number of cases users have reported that
music files saved on their computer were removed without their
permission. We’re taking these reports seriously as we know how
important music is to our customers and our teams are focused on
identifying the cause. We have not been able to reproduce this
issue, however, we’re releasing an update to iTunes early next
week which includes additional safeguards. If a user experiences
this issue they should contact AppleCare.
That sounds a little weird — not sure how they can safeguard against a bug if they can’t reproduce it.