Yes, I've noticed this too.
Apparently, you're supposed to use the space bar, which brings up a Quick Look preview window.
While this is OK if all you want to do is see a preview of an image (which I almost never do), it's not very helpful for the main use I have for Spotlight, which is to open an application and then choose the actual document.
Previously, all I had to do was cmd-space Sc enter tab and I had a list of Scrivener documents, which I could choose with the down arrow in the way nature intended.
Now it's cmd-spc Sc enter down-arrow space and use the stupid mouse to have to pick a document because the QuickView window doesn't get the focus.
This is not helpful – the whole point of Spotlight is that you don't have to waste time using the mouse, so why cripple the feature in this way?