As per title. Occasionally, it seems to work when I first turn on the game. Lets you swap between trucks, but not actually press x to select. You need to use the mouse or swap with the truck selection on the local map.

I can confirm.
Up to a certain moment it works, then no more. Selecting another map of the region also only works with the mouse.
You can press the button with the controller and it flashes on the monitor, but nothing happens.

@GD80 can you record a short video demonstating the problem? it will help in the investigation.