test failed in CI: test_omdb_success_cases (task `bfd_manager`)

This test failed on a CI run on #9188:

https://github.com/oxidecomputer/omicron/pull/9188/checks?check_run_id=52847486148

Log showing the specific test failure:

https://buildomat.eng.oxide.computer/wg/0/details/01K7MPNHDCE57B27BXXX7XQHN0/0eslPfQS1lgTXWRI6fZthegdAkqAsdoXsy1FHNoaYhzYU3CQ/01K7MPP2Y3PHSEH74QK8FN81ZW

Excerpt from the log showing the failure:

8292	2025-10-15T22:04:11.362Z	     task: "bfd_manager"
8293	2025-10-15T22:04:11.362Z	       configured period: every <REDACTED_DURATION>s
8294	2025-10-15T22:04:11.362Z	       last completed activation: <REDACTED ITERATIONS>, triggered by <TRIGGERED_BY_REDACTED>
8295	2025-10-15T22:04:11.362Z	         started at <REDACTED_TIMESTAMP> (<REDACTED DURATION>s ago) and ran for <REDACTED DURATION>ms
8296	2025-10-15T22:04:11.362Z	    -    last completion reported error: failed to resolve addresses for Dendrite services: proto error: no records found for Query { name: Name("_dendrite._tcp.control-plane.oxide.internal."), query_type: SRV, query_class: IN }
8297	2025-10-15T22:04:11.362Z	    +warning: unknown background task: "bfd_manager" (don't know how to interpret details: Object {})

At a glance it looks like this is a race between the task failing because it runs before internal DNS is available (or is able to resolve dendrite) and the task succeeding?

Start with the linked CI run for PR #9188 and the provided build log, focusing on the bfd_manager task and the Dendrite SRV lookup error. Trace how this failure is classified in the test output and determine whether DNS readiness or background-task reporting explains the mismatch. Done means the cause is established and the affected CI test no longer fails spuriously.