A family of Microsoft word processing software products for creating web, email, and print documents.
This has nothing to do with System Settings/Preferences. Why you were sent there I have no idea. The problem is that Microsoft has made some undocumented changes to keyboard combination assignments — ostensibly toward Mac/Windows parity. Apparently your 2 Macs are running different versions of Mac Office.
On the newer version use Shift+Option+Command+➖ instead.
Shift+Command+➖ now is assigned to Subscript but can be reassigned if you prefer.