Weak PI / trailing_user

Status: available. Complete, directly loadable models are published for the 4/8/16 cumulative-update milestones:

iter_0000003: 4 cumulative updates (2 inherited first_user + 2 trailing_user)
iter_0000007: 8 cumulative updates (2 inherited first_user + 6 trailing_user)
iter_0000015: 16 cumulative updates (2 inherited first_user + 14 trailing_user)

The migrated run was branched after zero-indexed iteration 1 while preserving the adapter, complete MTP state, AdamW moments, and dataset cursor. Therefore these are cumulative branched checkpoints, not a fresh trailing-user run from update 1.

There is no genuine one-update artifact: that would be iter_0000000, which is absent from the migrated archive. iter_0000001 is already two inherited first_user updates and must not be relabeled as a one-update trailing model.

Legacy unmerged split-bundle pointers remain available for iterations 1, 2, and 4: