The peer-edit delivery fence from #5882 treated an equal applied generation as stale. One edit legitimately fans out one delivery per peer record under a single generation (the ILM-expiry edit sends every peer's record), so the receiver applied only the first body, raised its high-water mark, and silently acked-success while dropping the rest — enableILMExpiryReplication never converged on receiving sites and the three-node nightly e2e failed deterministically (issue #5767).
Only a strictly newer applied generation is stale now. Equal generation implies the same logical edit and re-applying a delivery is idempotent (update_peer overwrites the peer record; the mark is raised with max), while strictly older deliveries — the cross-node ordering case the fence exists for — stay rejected.
Adds a composed unit test driving three same-generation bodies through the receiver's fenced sequence, and widens the replication e2e's two site-replication wait helpers from a 10s polling ceiling to the 30s deadline the file's other waits use.
Zhengchao An
2ad8ab534e