How to diagnose an undefined index in a fresh install of Drupal 7? Question:

How do I begin to explore what is causing this error? If this were reporting errors from a contrib module, I would submit a bug report on drupal.org. However, I'm not really sure where I should begin to submit an issue. 

Set up: 

I installed a Drupal 7 instance installed via Quick Drupal 

drush qd -y d7-mysite
cd mysite/drupal
php -S localhost:8080


And immediately installed needed modules via drush en -y field_collection_tabs workbench workbench_moderation


Field Collection 7.x-1.0-beta11, 
Field Collection Tabs 7.x-1.0-beta11, 
Workbench 7.x-1.2, and
Workbench Moderation 7.x-1.4.


Then the errors:

After a modicum of configuration to get work bench going and adding a writer user, I begin to see these error messages:


  Notice: Undefined index: #contextual_links in
  contextual_pre_render_links() (line 140 of
  /drupal/modules/contextual/contextual.module).
  
  Warning: Invalid argument supplied for foreach() in contextual_pre_render_links() (line 140 of
  /drupal/modules/contextual/contextual.module).
  
  Notice: Undefined index: #contextual_links in contextual_pre_render_links() (line 140 of
  /drupal/modules/contextual/contextual.module).
  
  Warning: Invalid argument supplied for foreach() in contextual_pre_render_links() (line 140 of
  /drupal/modules/contextual/contextual.module).
  
  Notice: Undefined index: #contextual_links in contextual_pre_render_links() (line 140 of
  /drupal/modules/contextual/contextual.module).
  
  Warning: Invalid argument supplied for foreach() in contextual_pre_render_links() (line 140 of
  /drupal/modules/contextual/contextual.module).


Location:

This is coming from a function called contextual_pre_render_links($element)

Other Tidbits:


This only happens when the Authenticated User creates new node. Administrator can create a node with out an error message displaying. 
I'm trying to implement a work-flow system using Workbench on an inherited site. I'm trying to understand this process so that I can teach others.
In this development copy I've turned off Contextual (drush dis contextual) which of course gets ride of the error message. 

I welcome any other answers that might offer a bit of enlightenment to me on this matter. We can live without the Contextual module's functionality but it does add some additional clicks to accomplish certain task.