Can you elaborate? My understanding is that this only happens in cases of tmj inflammatory issues like rheumatoid arthritis.
From what I've been able to deduct, every case of late relapse I've seen has been due to joint changes.
Whether those joint changes came from jaw surgery, some other condition, or a combination of both, I don't know. Surgeons (good ones at least) diagnose joint problems ahead of time and inform the patient of relapse and/or possibly even limit the movements.
Open bites are notorious for relapse years after the surgery. From what I can tell from looking at x-rays of patients (i.e. people on this forum who sent me their records for opinion) with this type of relapse, it again looks to be at the joint.
In general, if your joints are healthy and you don't have an open bite, you'll experience most of your relapse in the first year or so. But as mentioned, muscles pull on bone, and in any battle of muscle vs bone the muscle always wins. This battle will take place until there is equilibrium in the forces, so time can vary.