If you re-mapped jump to another button than Space, you will notice that it doesn't carry over to jumping while on Roach.

This is EXACTLY the same reason we still have to press E to Take loot, even if E has been re-mapped to something else (but, as yet there is still NO way to fix this particular keybind that I know of).

These hard-coded keys (at least as far as the keybinding page in Options) really need to be addressed.