The released Classic offline BC checkpoint's step subdirectory read 1000000000, from a convention that predates the current one. The canonical unit is the resolved env-frame budget, which this run's own resume_metadata.json records as OFFLINE_TOTAL_TIMESTEPS = 99942400 (1525 updates x 512 envs x 128 steps).
Contents are unchanged. Restoring from the renamed directory returns the identical parameter tree: 113 leaves, 9,334,289 parameters, checksum 3324.268310546875, verified before and after. Orbax resolves the latest step by directory name and the step number appears in no file inside the checkpoint, so loading is unaffected apart from the reported step.