Yes, the not working remapping of action is kinda the worst bug for me in the game.
I also have melee mapped to a mouse button, but when using it, switching optics doesn't work. Only the hardcoded F key works.
When downed, pressing the remapped jumping button (as indicated on the screen even) doesn't work either, only spacebar works...
When driving vehicles like the hovercraft or the jeep and using the arrow keys for driving (up arrow accelerating, left arrow to turn left etc.) is impossible in third person view because the camera keeps rotating whenever pressing arrow left or arrow right.
Please fix these hardcoded action mappings as soon as possible, this should not exist in code in a modern game these days.