The Distributed Tests / DBO test group on ROCm vLLM CI fails in build 11147 when successive DBO microbatches share one ROCm DeepEP buffer. The intranode path can publish queue progress without a complete producer/consumer ownership chain, while whole-workgroup barriers can pair unrelated per-rank rounds. This change uses per-rank wave barriers and release/acquire ordering for dispatch and combine tail publication, queue-slot reuse, receiver progress, retirement, and shared tail fan-out. It also adds a two-rank regression test that drives asymmetric and randomized microbatches through repeated queue wraparound on the same buffer.