We use Shared Filters in every segment. They include our standard exclusions that cannot be Master Exclusions. Example: we have a special audience that can only be communicated to after permission is given.
All users are trained not to manipulate these Shared Filters because any change in one segment cascades to every segment the Shared Filter is used in. However, sometime people forget and changes are made.
When anyone saves a segment with a Shared Filter then they become the last modifier of the Shared Filter. This makes it IMPOSSIBLE to find out who made the change so they can be re-trained to do the correct thing.
But, changing permissions doesn't work because they can only use the Shared Filters as a Local Copy, which would become a nightmare to manage if we had to change any of these filters.
Please either stop the save from updating the Last Modified field or add Shared Filters to the Audit Log!