Manage Events page and Edit Event produce inaccurate permissions error

Due to a permissions error, all users (even drupal user #1) cannot:

1. see the Manage Events listing at all (it's blank)
2. edit an event

This is currently a problem in CiviCRM.org as well as one of my client sites.  Although I don't have a exact source of the problem what these two sites have in common is:

• use of Participant Custom Data fields specific to an event or event type
• recently upgraded to 4.7.19 (was not a problem in 4.7.18)

I also notice there are several bugs in the queue in regards to API as it pertains to CiviEvent, and have to wonder if this is related in some way: CRM-20582, CRM-20581, CRM-20549

Debugging output is attached.  I hope that is helpful.