posted 9 years ago
Its not a huuuge deal unless it starts to unravel more, but will remain fully functional until that time. To prevent this you can use less torque when tightening the fixing nut or bolt, or replace your washer and fixing bolt. Some washer/ anchor bolt combinations are more proned to smashing and pulling a cable like that. Many modern derailleurs will have a washer with a little groove and a small piece that comes down and prevents the washer from spinning while the fixing bolt is being tightened. This prevents the cable from being pulled around the bolt as it tightens. Ideally the cable remains straight going in and out of the anchor bolt, but sometimes getting it that way is more trouble than its worth especially with front deraileurs it seems.
Other than being slightly weaker, now that cable poses a thumb pricking danger, handle with care!