Strikethrough keyboard shortcut on Macbook Pro

Every time I try to use the strikethrough keyboard shortcut in Scrivener 3 on my MBP, I hear a pop sound I assume is an alert but there is no strikethrough in the text I selected. Is this a bug, or am I doing something wrong? I’m using Shift-Command-_ on my keyboard. Maybe there’s an issue because - and _ are the same key on a MBP?

The presence of a noise indicates an error in most cases. Commands that go through successfully just do the thing they are meant to do, with no further ado.

If a shortcut isn’t working as I expect, I check the menu command itself. It’s not entirely reliable as another program may be globally stealing that shortcut, but it’ll at least let you know if Scrivener is trying to use it. And of course, I assume if you use the command manually it does work.