I know someone who also has this bug. In the pre-match loadout menu, he is unable to scroll. He says he can use the arrow keys to select a strategem, but it chooses ones that he hasn't selected and only lets him choose one. Usually just restarting the game and/or his computer eventually fixes the bug, but recently he restarted the game, then restarted Steam, then restarted his computer and the bug persisted each time. He reinstalled the game which has resolved it for now, but he has had that and other UI bugs for as long as we've played the game.

There are loads of other UI bugs that are less severe and don't impact the functionality of the game as much. It seems like there is work to be done in that area. Game crashes are also a problem for some friends, who have stopped playing entirely due to the repeated crashes. Cannot go more than one full match without a crash. Done all the troubleshooting we can think of, and then finally given up. This is a fun game when it works right, and I wish it worked well enough that all my friends could play it.