Link to build or pfq page.
https://luci-logdog.appspot.com/logs/chromeos/buildbucket/cr-buildbucket.appspot.com/8929455626711957056/+/steps/BinhostTest/0/stdout

build # for that buildbot.
https://cros-goldeneye.corp.google.com/chromeos/healthmonitoring/buildDetails?buildbucketId=8929455626711957056

Snippet of log that contains the failure.
21:42:04: ERROR: When we take out config-requested useflags ('chrome_internal',) for public/partner builds, grunt-android-pi-pre-flight-branch cannot find Chrome prebuilts (probably due to USE flag mismatch)
Build settings: _CompatId(arch='amd64', useflags=('accessibility', 'authpolicy', 'autotest', 'build_tests', 'buildcheck', 'cfi', 'chrome_debug', 'chrome_remoting', 'clang', 'cups', 'debug_fission', 'evdev_gestures', 'fonts', 'gold', 'grunt_march', 'highdpi', 'libcxx', 'nacl', 'opengles', 'ozone_platform_default_gbm', 'ozone_platform_gbm', 'runhooks', 'smbprovider', 'thinlto', 'v4l2_codec', 'vaapi', 'xkbcommon'), cflags=('-O2', '-pipe', '-march=amdfam10', '-g', '-fno-exceptions', '-fno-unwind-tables', '-fno-asynchronous-unwind-tables'))
Closest matching configs:
	Boards: set([_BoardKey(board='amd64-generic', useflags=())])
		USE changes: ['-grunt_march']
		Build settings: _CompatId(arch='amd64', useflags=('accessibility', 'authpolicy', 'autotest', 'build_tests', 'buildcheck', 'cfi', 'chrome_debug', 'chrome_remoting', 'clang', 'cups', 'debug_fission', 'evdev_gestures', 'fonts', 'gold', 'grunt_march', 'highdpi', 'libcxx', 'nacl', 'opengles', 'ozone_platform_default_gbm', 'ozone_platform_gbm', 'runhooks', 'smbprovider', 'thinlto', 'v4l2_codec', 'vaapi', 'xkbcommon'), cflags=('-O2', '-pipe', '-march=amdfam10', '-g', '-fno-exceptions', '-fno-unwind-tables', '-fno-asynchronous-unwind-tables'))
	Boards: set([_BoardKey(board='betty-arcnext', useflags=('chrome_internal',)), _BoardKey(board='betty', useflags=('chrome_internal',))])
		USE changes: ['-grunt_march']
		Build settings: _CompatId(arch='amd64', useflags=('accessibility', 'authpolicy', 'autotest', 'build_tests', 'buildcheck', 'cfi', 'chrome_debug', 'chrome_remoting', 'clang', 'cups', 'debug_fission', 'evdev_gestures', 'fonts', 'gold', 'grunt_march', 'highdpi', 'libcxx', 'nacl', 'opengles', 'ozone_platform_default_gbm', 'ozone_platform_gbm', 'runhooks', 'smbprovider', 'thinlto', 'v4l2_codec', 'vaapi', 'xkbcommon'), cflags=('-O2', '-pipe', '-march=amdfam10', '-g', '-fno-exceptions', '-fno-unwind-tables', '-fno-asynchronous-unwind-tables'))
	Boards: set([_BoardKey(board='caroline', useflags=('chrome_internal',)), _BoardKey(board='tricky', useflags=('chrome_internal',)), _BoardKey(board='reef', useflags=('chrome_internal',)), _BoardKey(board='eve', useflags=('chrome_internal',)), _BoardKey(board='caroline-arcnext', useflags=('chrome_internal',)), _BoardKey(board='cyan', useflags=('chrome_internal',)), _BoardKey(board='peppy', useflags=('chrome_internal',)), _BoardKey(board='coral', useflags=('chrome_internal',)), _BoardKey(board='nocturne', useflags=('chrome_internal',)), _BoardKey(board='eve-arcnext', useflags=('chrome_internal',)), _BoardKey(board='terra', useflags=('chrome_internal',))])
		USE changes: ['-grunt_march']
		Build settings: _CompatId(arch='amd64', useflags=('accessibility', 'authpolicy', 'autotest', 'build_tests', 'buildcheck', 'cfi', 'chrome_debug', 'chrome_remoting', 'clang', 'cups', 'debug_fission', 'evdev_gestures', 'fonts', 'gold', 'grunt_march', 'highdpi', 'libcxx', 'nacl', 'opengles', 'ozone_platform_default_gbm', 'ozone_platform_gbm', 'runhooks', 'smbprovider', 'thinlto', 'v4l2_codec', 'vaapi', 'xkbcommon'), cflags=('-O2', '-pipe', '-march=amdfam10', '-g', '-fno-exceptions', '-fno-unwind-tables', '-fno-asynchronous-unwind-tables'))

...

21:42:04: ERROR: When we take out config-requested useflags ('chrome_internal',) for public/partner builds, grunt-android-pi-pre-flight-branch-tryjob cannot find Chrome prebuilts (probably due to USE flag mismatch)
...
21:42:04: ERROR: When we take out config-requested useflags ('chrome_internal',) for public/partner builds, grunt-paladin cannot find Chrome prebuilts (probably due to USE flag mismatch)
...
21:42:04: ERROR: When we take out config-requested useflags ('chrome_internal',) for public/partner builds, grunt-pi-android-pfq cannot find Chrome prebuilts (probably due to USE flag mismatch)
...
21:42:04: ERROR: When we take out config-requested useflags ('chrome_internal',) for public/partner builds, grunt-postsubmit cannot find Chrome prebuilts (probably due to USE flag mismatch)
...
ERROR
[chromite.cbuildbot.binhost_test] PrebuiltCompatibilityTest.testDumping
Verify Chrome prebuilts exist for all configs that build Chrome. ... ok

======================================================================
ERROR: [chromite.cbuildbot.binhost_test] PrebuiltCompatibilityTest.testChromePrebuiltsPresent
Verify all builds that use Chrome have matching Chrome PFQ configs.
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/mnt/host/source/chromite/lib/cros_test_lib.py", line 276, in _stacked_tearDown
    target(obj)
  File "/mnt/host/source/chromite/cbuildbot/binhost_test.py", line 67, in tearDown
    self.fail('Fatal errors found in this test')
AssertionError: Fatal errors found in this test

----------------------------------------------------------------------
Ran 2 tests in 97.179s

FAILED (errors=1)
21:42:04: ERROR: 
return code: 1; command: /b/swarming/w/ir/cache/cbuild/repository/chromite/bin/cros_sdk 'PARALLEL_EMERGE_STATUS_FILE=/tmp/tmpXCLWzL' -- /mnt/host/source/chromite/cbuildbot/binhost_test -v '--log-level=debug' NoIncremental
cmd=['/b/swarming/w/ir/cache/cbuild/repository/chromite/bin/cros_sdk', 'PARALLEL_EMERGE_STATUS_FILE=/tmp/tmpXCLWzL', '--', '/mnt/host/source/chromite/cbuildbot/binhost_test', '-v', '--log-level=debug', 'NoIncremental'], cwd=/b/swarming/w/ir/cache/cbuild/repository, extra env={'PARALLEL_EMERGE_STATUS_FILE': '/tmp/tmpXCLWzL'}