SEPM is version 12.1 RU2 and the clients are on version 12.1 RU1 MP1. SEP clients installed on a system that has Windows 7 Professional Edition operating system displays the operating system as Windows 7 Ultimate Edition in the Computer status logs and the Clients tab.
Until SEP 12.1 RU1 MP1 all flavors of Windows 7 Operating system were treated as simply Windows 7 in the SEPM database. With 12.1 RU2 the different flavors of Windows 7 OS have been differentiated to display the exact type in the SEPM console clients tab and logs.
Upgrade all the affected clients to 12.1 RU2 to resolve the issue.
Please see the following KB article for migration to SEP 12.1 RU2.
SEPM - 12.1 RU2
Clients - 12.1 RU1 MP1
Operating system - Windows 7 Professional Edition