Plugins were updated, which forces changes to jobs that use plugins that include their version information.  Was looking at a job that had a recent change as shown by the job config history plugin.  The changes were all plugin version changes, and a specific user, not 'anonymous', was listed.  He shouldn't have access rights to update plugins.  I asked him if he did, he had no idea what I was talking about.

Looking at the list of similar issues, this might be a duplicate of