You only have to modify movement mode if it was “manually changed” prior to un-possess. It’ll hold its current state until re-possessed. In a lot of cases CMC will handle auto adjusting the state. Depends on few factors though.
If movement mode is set to walking at the time of unpossess and you teleport the character to a location mid air, then repossess, it will detect that its falling and set falling, then walking when it lands.