Where Is Post-Degradation Repair Limited? Evidence from Camera-Based 3D Occupancy

In camera-based 3D occupancy, post-deployment repair aims to recover task performance when observation quality degrades, and its effectiveness is commonly evaluated by the amount of performance recovered. Under a fixed model, a small final task gain indicates limited recovery but does not reveal where the repair process is constrained. Motivated by this ambiguity, we separate the analysis into local corrective evidence, privileged task gain, and inference-time task gain. We evaluate their relations using matched interventions across four nuScenes occupancy anchors and a controlled CARLA setting. This evaluation leads to three main observations. First, local corrective evidence can persist through finite-objective improvement while a positive task-metric advantage over the matched control remains unestablished. Second, a positive privileged task gain can correspond to substantially smaller or negative inference-time task gain. Third, inference-time task gain varies with allocation policy and prescribed intervention capacity, and can also change sign across semantic objectives even when the policy is fixed. In summary, these findings motivate examining how corrective evidence translates into finite task gain.