Looks like it might be this:
2018-09-17T20:23:37.314253-07:00 NOTICE arc-kmsg-logger[9895]: <3>init: Could not start service 'vendor.hwcomposer-2-1' as part of class 'hal': File /vendor/bin/hw/android.hardware.graphics.composer@2.1-service-cheets(labeled "u:object_r:vendor_file:s0") has incorrect label or no domain transition from u:r:init:s0 to another SELinux domain defined. Have you configured your service correctly? https://source.android.com/security/selinux/device-policy#label_new_services_and_address_denials

Ah, no, maybe more obvious: TestFail: Could not find bugreportd, mini container not running?

bugreportd was removed and replaced with "arc-bugreportd" in https://googleplex-android-review.git.corp.google.com/c/device/google/cheets2/+/5009619

https://chrome-internal-review.googlesource.com/c/chromeos/autotest-cheets/+/680968 up for review.

Looks like erosky@ already uploaded a change at https://chrome-internal-review.googlesource.com/c/chromeos/autotest-cheets/+/680356

The test in CQ with the change #3 is failing with "arc-bugreportd, mini container not running?"

That's understandable, because PFQ failing means the current ARC-P image that ChromeOS CQ uses is not updated to the new name yet...

The following revision refers to this bug:
  https://chrome-internal.googlesource.com/chromeos/autotest-cheets/+/4c37ed1bf278b22438ae2dfba3a55badd682415c

commit 4c37ed1bf278b22438ae2dfba3a55badd682415c
Author: Evan Rosky <erosky@google.com>
Date: Wed Sep 19 06:49:12 2018

both pi_android_pfq and cheets_LoginScreen_P are back to green now.

https://stainless.corp.google.com/search?view=matrix&row=build&col=test&first_date=2018-09-13&last_date=2018-11-09&test=cheets_LoginScreen_P&exclude_cts=true&exclude_not_run=false&exclude_non_release=true&exclude_au=true&exclude_acts=true&exclude_retried=true&exclude_non_production=false