These happen with nearly every shifter, no matter what type you're using. The failure mode is fatigue on bends.
The problem is that bend diameter ratio of cables should be 72 for long life, with 42 being an absolute minimum.
This means bending diameter of 1.2mm cables should be 86.4 mm with 50.4 mm being an absolute minimum. Thus, the bending radius should be 43.2 mm with 25.2 mm being an absolute minimum.
I think you'll find that nearly every shifter, including many types of trigger shifters (STI or Rapidfire MTB) and the most durable ones like downtube, thumb and bar-end shifters violate this rule pretty severely.
Thus, the cable will fail unless replaced. How long it takes to fail depends on how many times you use the shifter per kilometer and how many kilometers you ride per year. This illustrates that it may not be such a good idea to continually shift on a "corncob" road cassette having 11-12-13-14-15-16-17-... tooth sprockets. It may be a better idea to use a cassette having few sprockets, large jumps between gears and only shift when you truly need to shift, i.e. when encountering such a steep uphill that you can't tolerate it with your usual flatland gear.
Fortunately, the cable will last far longer than for example a Di2 battery charge, so we need not move to electronic shifting. All it requires is replacing the cable every year or two. Usually the shifter designs make it reasonably easy to change the cable. In contrast with drop bar "aero" brake levers with under-the-bar-tape cable routing, in which case changing the brake cable might require rewrapping the bar tape because you might not be able to hit the housing taped under the bar tape no matter how many times you try (at least this is a problem with BL-R400), shift cable replacement is easy.
By the way, cable failures can happen for brakes too (they having 1.6mm diameter should have ideally 57.6 mm bending radius and 33.6 mm bending radius at a minimum -- in many cases, this bending radius limit is observed and thus the failure is not due to fatigue but rather due to wear). In this case, it's a safety hazard. Installing a new brake cable every now and then is recommended.