Any time you are jumping or bouncing the front end under throttle you usually incur breakage of something whether it is locked or not. That being said I broke my first CV in a few years (bouncing on a wet step). I am running ARB's on both ends, homemade steel front diff, 2.7 V6, and 33X12.5X15's. If you are hard on the skinny pedal, you it will cost you.
When running on Moab's slick rock (sandstone) turning with even the rear locked takes a lot more effort, with both locked it just wants to go straight. But that is the benefit of selectables, flip a switch on or off.