What do you mean 'Nope'
When I start CS, the 'spreadsheet' contains all the books in the library with the first item highlighted, when I press the down arrow I can then only see the first item - IMO the highlight should move to the second item.
I didn't type
^.+$ into the regex search box, I didn't press the Search pushbutton, and I didn't select Authors as the Filter.
Aa-ah - If you look at the second screen shot it has "Anat Admati..." displayed in the Author Filter, so it seems that when CS starts the Authors Filter selector has keyboard focus, even though the dominant visual appearance is that the topmost row on the spreadsheet has focus.
Maybe its been ever thus - but in my opinion when CS starts the first column in the first row should have keyboard focus.
FWIW: I start CS via the keyboard from calibre's context menu, i.e. I'm in keyboard mode - (menu key, up, right, enter)
BR