Opening an SSE stream is a single unretried request bounded by RendezvousClientOptions.RequestTimeout. On the release runner the suite shares a builder container with parallel image builds, so the loopback handshake can lose its whole wall-clock budget to thread-pool starvation; the client then reports a typed ServiceUnavailable that the test asserted against as if it were the reset event. Retry the open from the same replayable cursor, raise the per-request budget to the contract ceiling, and drop protocol keepalives so a slow interval between assertions cannot be mistaken for a session event. The retry only fires on the transport failure the stream endpoint can never produce as an envelope, is bounded, and yields the final failure verbatim, so a genuinely broken stream still fails.