switch to crouched position, press "2xC" or using the old default binding "Right Shift" to use "Toggle raise weapon"

now the weapon is lowered.

press "Toggle raise weapon" or "raise weapon", now the weapon should be raised, but it isn't.

trying the same while standing and everything works correctly.

if you are in prone position pressing "Toggle raise weapon" makes the soldier stand, it would be better if he switched to crouched, or didn't do anything.