Experienced on experimental multiplayer server. On opening the keymapping menu, the menu pops up in a wrong way. The actual menu "window" is empty (first picture), exept for the "tabs" for Infantry/vehicle/etc. and the dropdown menu. At the same time all the keymapping settings are shown "behind" the window, covering the whole screen and not disappearing after closing the menu. (second picture)

They only disappear on leaving the server (or logging into a server, it can also happen in the main menu). The game itself continues to run in the background without problems, but is unplayable, because the whole screen is covered with the menu.
Not sure if needed: