We have a process built with Process Builder, that updates a customer field on Account from a related object. When the related object is created, it copies a date from the related object, to a date field on the account.
Some accounts are not getting updated properly, which got me digging. I found that the users who are executing the update on the related object are assigned a security profile with Read Only access to the field on the Account object. However, when I log in as one of those users, the process updates the read only field with no problem.
I checked the effective permissions on that field, and it does indicated that profile has read only access.
I also enabled change tracking on that field and it shows the user with the read only access to that field made the change.
I checked for any permissions sets that might be enabling write access to that field, and there are none.
So how can a user, whose security profile has read only access to a field, execute a process that updates that field?