On multiple sites I own the Content Template for certain Custom post types suddenly switched.
For example, on one website I have a View Template 'School Single Page' and 'Agenda single page'
All Agenda custom post types are automatically given the 'Agenda single page' view template through the View options (view the image in the attachment)
Suddenly all Agenda custom post types now have the 'School single page' view template assigned to them. This has just automatically happened (on more than one site), without anyone touching the site.