If a search results in the "We haven't found anything" message (e.g. searching for a quoted string or a verbatim result) then most of the keyboard controls/shortcuts fail to trigger.
I had searched for an error message (in quotes) and did not find anything. I hit / expecting to be focused in the search bar so I could edit my search. Instead, the browser search activated. The ! shortcut was also not responding.
? and shift-~ did work as usual.
n, i, m, a, q etc did not work to access those search areas/features, which mostly make sense (perhaps with the exception of maps).
Tested under Firefox on Linux and Chrome on Win10.