noel@ - is this something we have test coverage for?

Yes, we have tests for file zip/inzip, and for offline state drawing, but not both at the same time.

sammc@ Any recent changes in the they way offline state is drawn that would change how unzipped files are displayed ( issue 878278  maybe, not sure)

Yes, we have tests for file zip/inzip, and for offline state drawing, but not both at the same time.

sammc@ Any recent changes in the they way offline state is drawn that would change how unzipped files are displayed ( issue 878278  maybe, not sure)

For reference this applies to all FSP's not just zip.

Also the build number (3538) seems to suggest this might have been merged to M70.

I suspect it's https://cs.chromium.org/chromium/src/ui/file_manager/file_manager/foreground/js/ui/file_table_list.js?l=208&rcl=8afa556d50e487ea827a52f3b01d391cf4a71c90 treating undefined as falsy.  Issue 878278  removed limiting dimming when unavailable offline to within "My Drive" and so exposed this problem.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/2de7c56fdc95f1aa2a090b7c4bb090b160352da3

commit 2de7c56fdc95f1aa2a090b7c4bb090b160352da3
Author: Sam McNally <sammc@chromium.org>
Date: Wed Sep 19 01:34:13 2018

Treat files without an availableOffline property as available offline.

Currently, the dim-offline class is added to any files either with
availableOffline set to false or undefined. It should only be applied to
files with availableOffline set to false. Explicitly check for equality
to false rather than relying on truthiness.

Bug:  885302 
Change-Id: If948f161d64dc34280a12f275cd6f07e98356030
Reviewed-on: https://chromium-review.googlesource.com/1232795
Commit-Queue: Noel Gordon <noel@chromium.org>
Reviewed-by: Noel Gordon <noel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#592296}
[modify] https://crrev.com/2de7c56fdc95f1aa2a090b7c4bb090b160352da3/ui/file_manager/file_manager/foreground/js/ui/file_table_list.js

This bug requires manual review: M70 has already been promoted to the beta branch, so this requires manual review
Please contact the milestone owner if you have questions.
Owners: benmason@(Android), kariahda@(iOS), geohsu@(ChromeOS), abdulsyed@(Desktop)

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

Manually verified in Canary 71.0.3558.0.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/f1dcc2bf6884143d80e15e41cc14791ce1e9406a

commit f1dcc2bf6884143d80e15e41cc14791ce1e9406a
Author: Sam McNally <sammc@chromium.org>
Date: Mon Sep 24 22:50:34 2018

Treat files without an availableOffline property as available offline.

Currently, the dim-offline class is added to any files either with
availableOffline set to false or undefined. It should only be applied to
files with availableOffline set to false. Explicitly check for equality
to false rather than relying on truthiness.

Bug:  885302 
Change-Id: If948f161d64dc34280a12f275cd6f07e98356030
Reviewed-on: https://chromium-review.googlesource.com/1232795
Commit-Queue: Noel Gordon <noel@chromium.org>
Reviewed-by: Noel Gordon <noel@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#592296}(cherry picked from commit 2de7c56fdc95f1aa2a090b7c4bb090b160352da3)
Reviewed-on: https://chromium-review.googlesource.com/1241915
Reviewed-by: Sam McNally <sammc@chromium.org>
Cr-Commit-Position: refs/branch-heads/3538@{#628}
Cr-Branched-From: 79f7c91a2b2a2932cd447fa6f865cb6662fa8fa6-refs/heads/master@{#587811}
[modify] https://crrev.com/f1dcc2bf6884143d80e15e41cc14791ce1e9406a/ui/file_manager/file_manager/foreground/js/ui/file_table_list.js

The following revision refers to this bug: 
https://chromium.googlesource.com/chromium/src.git/+/f1dcc2bf6884143d80e15e41cc14791ce1e9406a

Commit: f1dcc2bf6884143d80e15e41cc14791ce1e9406a
Author: sammc@chromium.org
Commiter: sammc@chromium.org
Date: 2018-09-24 22:50:34 +0000 UTC

Treat files without an availableOffline property as available offline.

Currently, the dim-offline class is added to any files either with
availableOffline set to false or undefined. It should only be applied to
files with availableOffline set to false. Explicitly check for equality
to false rather than relying on truthiness.

Bug:  885302 
Change-Id: If948f161d64dc34280a12f275cd6f07e98356030
Reviewed-on: https://chromium-review.googlesource.com/1232795
Commit-Queue: Noel Gordon <noel@chromium.org>
Reviewed-by: Noel Gordon <noel@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#592296}(cherry picked from commit 2de7c56fdc95f1aa2a090b7c4bb090b160352da3)
Reviewed-on: https://chromium-review.googlesource.com/1241915
Reviewed-by: Sam McNally <sammc@chromium.org>
Cr-Commit-Position: refs/branch-heads/3538@{#628}
Cr-Branched-From: 79f7c91a2b2a2932cd447fa6f865cb6662fa8fa6-refs/heads/master@{#587811}