Answer
The Base Profile(s) assigned to your regular users need to be manually updated too — refreshing the server cache alone doesn't propagate new custom-field/layout visibility into existing profiles. Open the relevant Base Profile, set it active in your current session, navigate to the screen with the new field, right-click it and choose Properties > Layout, check the box to make the new field visible, position/size it as needed, then go to Tools > Options and save the active profile. Once the Base Profile itself has been updated this way, regular users assigned to that profile will see the new field/layout on their next login.