The material design ink effect that I think you're mentioning is a holdover from the "Use compact alerts view" feature that still occurs while collapsing and expanding alerts is disabled. 

It'd be easy to remove though I've also considered: what if we just made alerts able to be expanded or collapsed by default and then changed the "Use compact alerts view" option into a "Collapse alerts by default" option or something instead.

The following revision refers to this bug:
  https://chromium.googlesource.com/infra/infra/+/3c2c71870f0655781f6a4538deaad7c827a44e95

commit 3c2c71870f0655781f6a4538deaad7c827a44e95
Author: Tiff Zhang <zhangtiff@google.com>
Date: Wed May 17 18:49:12 2017

SoM: Remove animation from collapsing/expanding alerts + misc polish.


Bug:712816
Bug:719740

Change-Id: I3a62a53c23c3575c89d1d4a764f27cc2b81b7193
Reviewed-on: https://chromium-review.googlesource.com/506456
Reviewed-by: Sean McCullough <seanmccullough@chromium.org>
Commit-Queue: Tiffany Zhang <zhangtiff@chromium.org>

[modify] https://crrev.com/3c2c71870f0655781f6a4538deaad7c827a44e95/go/src/infra/appengine/sheriff-o-matic/elements/som-alert-item/som-alert-item.html
[modify] https://crrev.com/3c2c71870f0655781f6a4538deaad7c827a44e95/go/src/infra/appengine/sheriff-o-matic/elements/som-alert-item/som-alert-item.js
[modify] https://crrev.com/3c2c71870f0655781f6a4538deaad7c827a44e95/go/src/infra/appengine/sheriff-o-matic/elements/som-drawer/som-drawer.html
[modify] https://crrev.com/3c2c71870f0655781f6a4538deaad7c827a44e95/go/src/infra/appengine/sheriff-o-matic/bower.json

This should be fixed and out with the next push. :)