All commands like /fill, /clone, etc, the commands which has functions with cordinates, ain't taking the inputs of cords correctly, the command is having issue in identifying the cordinates of "to" and "from" function, resulting in wrong inputs of cordinates. Basically there is sum bug with the input function of cords in the commands.

In the video we can clearly see that before completion of "from" cords, it started taking up "to" cords and it's not only happening with /fill command, it's happening with all the commands with cordinates requirement.