The short answer is you can have any two out of relativity, causality and faster than light travel, so yes, Traveller jump drives can cause time travel. However, to do so to any noticeable degree involves accelerating to relativistic velocities, so if you either use real propellant requirements or handwave an upper limit to the velocities achievable using impellor plates in some way, or, I think, require a ship to be at rest (or at least moving very slowly) relative to the local gravitational field, it won't realistically be a problem.