Blank page when adding a Group as a parent of a Space

When I try to add a group to a space (using the space/members/inherited tab) I am redirected to a blank screen @ my.site/node/1/members. I then navigate back to the space page/members/ inherited tab and the UI shows that no group has been added to the space.

Steps to reproduce

1. Created a top level space name "ibm_admin"

• private
• group user inheritance: Yes - subgroups of this group will inherit its users
• Group user permission inheritance: Inherit Permissions - inherited users in this group's subgroups will have the permissions as they do in this group and not the permissions of generic members of that subgroup

2. Created sub-space in ibm_admin called "Hive Administration"

• Group user inheritance: Yes - subgroups of this group will inherit its users.
• Group user permission inheritance: Inherit Permissions - inherited users in this group's subgroups will have the permissions as they do in this group and not the permissions of generic members of that subgroup
• Group roles and permissions: Use default roles and permissions

3. Created custom content type "Company"

• Added couple fields including existing fields for og_group_ref and oa_section_ref
• Added field group to hold og_group_ref and ao_section_ref
• Visit OA Section Templates (http://dev-mikeg.pantheon.io/admin/openatrium/section-templates), clone Document Section and change to Company Section. NOTE - Storage states Normal after cloning; others are labeled default (not sure why this is)
• Visit Taxonomy and add a entry for Company in the Section Type taxonomy. Section layout set to "Company Section" (just created in OA Sections) and in Node Types only checked item is "Create Company

4. Add a section to Hive Administration space called Companies.
5. Add 2 company nodes to section to test
6. Content not showing on section page so I customized layout to remove all widgets except body. Then added View: Open Atrium Content: Recent Content pane to layout. Companies now display on section page.
7. Created a group named "IBM - Project Admin" by visiting members button of ibm_admin space

• Group visibility: Private - accessible only to space members
• Group user permission inheritance: Inherit Permissions - inherited users in this group's subgroups will have the permissions as they do in this group and not the permissions of generic members of that subgroup
• Group roles and permissions - Use default roles and permissions

8. Added the group to the space ibm_admin via members/inheritance tab. Blank screen (http://dev-mikeg.pantheon.io/node/1/members) appears after selecting "IBM - Project Admin" from text and hitting Add Group
9. Reloading this page now gives an error - Fatal error: Allowed memory size of 268435456 bytes exhausted (tried to allocate 32 bytes) in /srv/bindings/8fcb62c7d0a14b4d91691a36d98901d7/code/includes/bootstrap.inc on line 3441

Original issue text below
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I have been having issues working with Groups and space permissions. I have recreated an issue I was having on Pantheon @ http://dev-mikeg.pantheon.io/admin/modules (the old issue is here - https://www.drupal.org/node/2625954). The Pantheon instance is an out of box version of Atrium with no additional modules enabled. The instance has 1 custom content type added that include references to og_group_ref and oa-section_ref.

The issue occurs when I try to add a group to a space (space/members/inherited tab). At this point I am redirected to a blank screen @ http://dev-mikeg.pantheon.io/node/1/members. I then navigate back to the space page/members/ inherited tab and the UI shows that no group has been added to the space.

On Pantheon this renders a blank white screen. I believe I recreated this accurately from a SoftLayer instance (referenced in old issue) which gives a php memory error.

regards,
mikeg