If you type not fast enough in the search field of the user directory, the focus shifts to 
Received, leading to the activation of keyboard shortcuts if you don’t notice.
Short screencast of the focus shift:
And one where, by trying to add a “u”, the keyboard shortcut is triggered:
Copied from here:
When I’m searching for a group name here and start to type, the search is filtered according to all the symbols I already typed after each symbol. I can wait as long as I want between the symbols.
However, when I search for a username here, after each symbol, I must type the next symbol after not more than ~0.4Sec or else, the results are filtered, and the cursor is no longer inside the search window, so I cannot continue typing (unless I put the cursor back inside the search window again and again after each symbol).
I reckon 0,2 sec is closer 
It has been such as long I’ve used Discourse. That’s why I think it is un-usable and I as an admin go to admin side if I need to operate with users.
Just merged a fix which should prevent this behaviour: FIX: Prevent focus shift when navigating the user directory by nattsw · Pull Request #29209 · discourse/discourse · GitHub
I also have the impression that your changes also broke the User Card Directory component. At least I can no longer click on “ received” or “ given” in the cards view to change the order.
Appreciate your callout here @moin!
It also turns out there was another component affected
I’ll close this topic next week in case there are more that pops up but I did a quick scan and it looks like we’re fine.
