Several agent sessions sharing one repository gave us the file-level cousin of this, and the fix that stuck was banning git add -A and routing every push through a fetch, rebase, push wrapper, because the worktree was shared even when the sessions were not. I will keep "liveness is not ownership" as the sentence from it. Once every session has its own stack in the next post, do the assert-ownership and assert-served-bytes steps stay in as the thing that tells you the isolation leaked?