Use the Copy command copy something (in this case a polyline, but that shouldn’t matter) and click anywhere; type F and hit space, now the From Last Point is checked, however, the f and space remain in the command line. So in order to also check the U or S box, you need to delete the space and the f and then type the shortcut letter and hit space. This is not an issue when you hit return, but I usually hit space.
I don’t remember this always being an issue on the mac, but maybe I’m wrong.
If I also click too fast the copy doesn’t register, I don’t recall this being an issue either, and only could find the adjustment for the right-click pop-up menu delay.