These fields which are everywhere but you don’t really pay attention to really mean something worth.
So if you feel you want to get hold of someone for modifying a record. Maybe also take a look at Modified By (Delegate) just in case so that the actual user might be someone else who wanted to do another thing on that record. 🙂
Impersonation is one of the basic aspects of a plugin step that you need to carefully design to let another user (usually Admins for most implementations) make the plugin run under their context instead of giving more security roles/privileges to every other new user.
Well, same goes for Created By & Created By (Delegate) also!
Usually, when you update something on a record, the Modified By is updated as expected. But notice that Modified By (Delegate) is not updated.
That’s because you are the rightful owner of the record and there’s no other person involved.
But what is someone else is modifying the record (who don’t have access to that record)?
In that case, Modified On (Delegate) field is populated with the name of that user. In such scenarios, Modified By (Delegate) user is the one who caused changes to the record.
Why Modified By (Delegate) was populated
The reason this was populated was because the record was updated through a plugin by a user who doesn’t have Write access to the record.
But because the user invoked a plugin which was Impersonating as a User who has rights to the records, the record was successfully updated. And this, the actual user who called the plugin is the one who will be populated in the Modified By (Delegate) field.
Hope this quick tip helps!