Hmm. I can't see the pop on the device in front of me, although I'm using a fairly dark wallpaper that doesn't have edges as contrasty as the default:

Google Chrome	63.0.3239.116 (Official Build) (64-bit)
Platform	10032.75.0 (Official Build) stable-channel eve

I don't see this on my current stable-channel eve:
63.0.3239.116 (Official Build) (64-bit)
Platform	10032.75.0 (Official Build) stable-channel eve

I do see it on my beta-channel samus:
Chrome 64.0.3282.79
Platform 10176.41.0

I'm not sure why I don't see it anymore on eve. It's quite noticeable on the samus.

+Aga, I believe there was a CL that postponed removing the wallpaper blur. Is this an intended change?

Postponing removal of blur was intentional to match blurring wallpaper at the beginning of lock screen transition. (https://crbug.com/789320)
 

What does it look like if we slow down the animation significantly for debug purposes? This blur animation is affected by crbug.com/803153 but it's hard to see if that's the only artifact when the animation is that fast.

#6, I do not remember we change the blur radius of wallpaper in the animation?

I can't tell from the video provided, Is there a slight 1 or 2 pixel jump at a very small blur radius (< 0.25 sigma) and then back when the radius reaches 0? If so, then this could be  bug 795528 . This is fixed in 65. 

herb, do you know when the fix for  bug 795528  rolled into chrome? I was seeing this on r528837, circa Jan 12.

Unfortunately I'm remote in Sydney and don't have a good way to test high speed animations locally on self-built chrome.

I still see the issue on samus on beta channel after update to this version:
64.0.3282.87 (Official Build) beta (64-bit)
Platform	10176.47.0 (Official Build) beta-channel samus

Is anyone else seeing this locally?

I think postponing removal of the blur is causing that effect: wallpaper is blurred and then at the end it turns unblured (does this sound accurately).

I will try to remove that effect and captures some videos, so we can confirm.   

[1] Blur removal delayed when unlocking:
https://drive.google.com/open?id=1Bx8BdJbn6rXctwh9friTuJeYyB4p5SJt

[2] No blur removal delay:
https://drive.google.com/open?id=1gGXtdR8Cf4SfUBBf9mBn26Xynzs7Rm0p

James, Is that the effect that you mean?

CL to remove delay:
https://chromium-review.googlesource.com/c/chromium/src/+/872128   

I *think* that's the same thing I saw, but I cannot be 100% sure from the videos. It might help to show someone in person in your office.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/f341c59bc188013f67ccd7498806293d5e5802e2

commit f341c59bc188013f67ccd7498806293d5e5802e2
Author: Aga Wronska <agawronska@chromium.org>
Date: Fri Jan 19 20:07:26 2018

Do not delay removing of the blur when unlocking.

Bug:  801632 
Change-Id: I559c747a7bd92df052258ef2e18b469e9fe09ef1
Reviewed-on: https://chromium-review.googlesource.com/872128
Reviewed-by: James Cook <jamescook@chromium.org>
Commit-Queue: Aga Wronska <agawronska@chromium.org>
Cr-Commit-Position: refs/heads/master@{#530594}
[modify] https://crrev.com/f341c59bc188013f67ccd7498806293d5e5802e2/ash/session/session_controller.cc
[modify] https://crrev.com/f341c59bc188013f67ccd7498806293d5e5802e2/ash/session/session_controller.h
[modify] https://crrev.com/f341c59bc188013f67ccd7498806293d5e5802e2/ash/wallpaper/wallpaper_controller.cc

Might  issue 803712  be a duplicate of this?

This should be resolved now. 

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/e0709d867f8e471c8e99132bab49055367287f02

commit e0709d867f8e471c8e99132bab49055367287f02
Author: Aga Wronska <agawronska@chromium.org>
Date: Mon Jan 29 18:28:37 2018

Do not delay removing of the blur when unlocking.

Bug:  801632 
Change-Id: I559c747a7bd92df052258ef2e18b469e9fe09ef1
Reviewed-on: https://chromium-review.googlesource.com/872128
Reviewed-by: James Cook <jamescook@chromium.org>
Commit-Queue: Aga Wronska <agawronska@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#530594}(cherry picked from commit f341c59bc188013f67ccd7498806293d5e5802e2)
Reviewed-on: https://chromium-review.googlesource.com/889598
Reviewed-by: Wenzhao (Colin) Zang <wzang@chromium.org>
Cr-Commit-Position: refs/branch-heads/3325@{#141}
Cr-Branched-From: bc084a8b5afa3744a74927344e304c02ae54189f-refs/heads/master@{#530369}
[modify] https://crrev.com/e0709d867f8e471c8e99132bab49055367287f02/ash/session/session_controller.cc
[modify] https://crrev.com/e0709d867f8e471c8e99132bab49055367287f02/ash/session/session_controller.h
[modify] https://crrev.com/e0709d867f8e471c8e99132bab49055367287f02/ash/wallpaper/wallpaper_controller.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/0394210794512fef580b28375535f4056d9444f0

commit 0394210794512fef580b28375535f4056d9444f0
Author: Aga Wronska <agawronska@chromium.org>
Date: Tue Jan 30 20:14:42 2018

Do not delay removing of the blur when unlocking.

TBR=agawronska@chromium.org

(cherry picked from commit f341c59bc188013f67ccd7498806293d5e5802e2)

Bug:  801632 ,  803712 
Change-Id: I559c747a7bd92df052258ef2e18b469e9fe09ef1
Reviewed-on: https://chromium-review.googlesource.com/872128
Reviewed-by: James Cook <jamescook@chromium.org>
Commit-Queue: Aga Wronska <agawronska@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#530594}
Reviewed-on: https://chromium-review.googlesource.com/891695
Cr-Commit-Position: refs/branch-heads/3282@{#621}
Cr-Branched-From: 5fdc0fab22ce7efd32532ee989b223fa12f8171e-refs/heads/master@{#520840}
[modify] https://crrev.com/0394210794512fef580b28375535f4056d9444f0/ash/session/session_controller.cc
[modify] https://crrev.com/0394210794512fef580b28375535f4056d9444f0/ash/session/session_controller.h
[modify] https://crrev.com/0394210794512fef580b28375535f4056d9444f0/ash/wallpaper/wallpaper_controller.cc