The Created By and Modified Last By Filters are missing for users in Vault.
The users do not have the View User Information and User Filters Vault Actions permissions enabled, restricting them from seeing it.
To enable the Filters:
- Navigate to: Admin --> Users & Groups --> Permission Sets --> [Custom Permission Set] --> Application.
- Select the Edit button.
- Enable the View User Information and User Filters Vault Actions
- Save changes.
Having the View User Information and User Filters Actions checked gives users access to the Filters.
Vault Permissions Documentation: About Permission Sets