The crash is not related to play store app nor octopus. It happens when an app at a page's last slot and another app at the next page's first slow has the same position ordinal.

Oh, yes, that makes sense to me. I am working on a CL to fix this.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/f21d67fe489fb239ae13b0148eb0a2f5d98801a2

commit f21d67fe489fb239ae13b0148eb0a2f5d98801a2
Author: Weidong Guo <weidongg@chromium.org>
Date: Thu Aug 16 00:38:47 2018

Fix crash caused by adding page break item

Background:
A crash will happen when a page break item is added between two items
with the same position.

Changes:
Fix the position of items before adding page break item.

AppListItemListTest.AddPageBreakItem
AppListItemListTest.AddPageBreakItemWithSamePosition

Bug:  874619 
Test: 
Change-Id: I7e5c9eac51db0fa7a563cb0097c13ab1777218fa
Reviewed-on: https://chromium-review.googlesource.com/1176560
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Commit-Queue: Weidong Guo <weidongg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#583466}
[modify] https://crrev.com/f21d67fe489fb239ae13b0148eb0a2f5d98801a2/ash/app_list/model/app_list_item_list.cc
[modify] https://crrev.com/f21d67fe489fb239ae13b0148eb0a2f5d98801a2/ash/app_list/model/app_list_item_list_unittest.cc

 Issue 877808  has been merged into this issue.