Looks like a timeout issue:

@@@BUILD_STEP@MasterSlaveSyncCompletion@@@
************************************************************
** Start Stage MasterSlaveSyncCompletion - Sun, 10 Jul 2016 23:37:02 -0700 (PDT)
** 
** Stage that records whether we passed or failed to build/test manifest.
************************************************************
23:37:02: INFO: Recording status fail for ['lumpy-pre-flight-branch']
23:37:02: INFO: RunCommand: /b/cbuild/shared_internal/.cache/common/gsutil_4.19.tar.gz/gsutil/gsutil -o 'Boto:num_retries=10' cp -v -- /tmp/cbuildbot-tmpKGHctP/cbuildbot-tmp7WJKRS/tmpNPdWHw gs://chromeos-manifest-versions/builder-status/8350.52.0-rc4/lumpy-pre-flight-branch
23:37:03: INFO: Running cidb query on pid 11949, repr(query) starts with 'SELECT deadline >= NOW(), TIMEDIFF(deadline, NOW()) from buildTable where id = 943672'
23:37:03: INFO: Running cidb query on pid 11949, repr(query) starts with <sqlalchemy.sql.expression.Select at 0x6224150; Select object>
23:37:03: ERROR: No status found for build config lumpy-pre-flight-branch.
23:37:03: INFO: Still waiting for the following builds to complete: ['lumpy-pre-flight-branch']
23:37:03: INFO: 0:00:00 until timeout...
23:37:03: INFO: RunCommand: /b/cbuild/shared_internal/.cache/common/gsutil_4.19.tar.gz/gsutil/gsutil -o 'Boto:num_retries=10' cat gs://chromeos-manifest-versions/builder-status/8350.52.0-rc4/lumpy-pre-flight-branch
23:37:04: ERROR: Not all builds finished before timeout (0 minutes) reached.

@@@STEP_LINK@lumpy-pre-flight-branch: The SyncChrome stage failed: <class 'chromite.lib.cros_build_lib.RunCommandError'>: return code: 1; command: /b/cbuild/shared_internal/chromite/bin/sync_chrome --reset --internal --tag 52.0.2743.73 /b/cbuild/shared_internal/.cach@https://uberchromegw.corp.google.com/i/chromiumos.release/builders/lumpy-pre-flight-branch%20release-R52-8350.B/builds/143@@@

@@@STEP_WARNINGS@@@
23:37:04: WARNING: The following builders failed with this manifest:
lumpy-pre-flight-branch
Please check the logs of the failing builders for details.

@@@STEP_FAILURE@@@
23:37:04: ERROR: 
23:37:04: INFO: Running cidb query on pid 11949, repr(query) starts with <sqlalchemy.sql.expression.Update object at 0x622ef50>
23:37:04: INFO: Running cidb query on pid 11949, repr(query) starts with <sqlalchemy.sql.expression.Insert object at 0x6224710>
************************************************************
** Finished Stage MasterSlaveSyncCompletion - Sun, 10 Jul 2016 23:37:04 -0700 (PDT)
************************************************************
23:37:04: INFO: Running cidb query on pid 11949, repr(query) starts with <sqlalchemy.sql.expression.Insert object at 0x62245d0>
23:37:04: INFO: Running cidb query on pid 11949, repr(query) starts with <sqlalchemy.sql.expression.Update object at 0x6224b90>
23:37:05: INFO: Running cidb query on pid 11949, repr(query) starts with <sqlalchemy.sql.expression.Update object at 0x6224c90>

Build link:
https://uberchromegw.corp.google.com/i/chromeos_release/builders/lumpy-pre-flight-branch%20release-R52-8350.B/builds/143

Logs link:
https://uberchromegw.corp.google.com/i/chromeos_release/builders/lumpy-pre-flight-branch%20release-R52-8350.B/builds/143/steps/MasterSlaveSyncCompletion/logs/stdio