I really wish you could learn how to take a diagnostic video.
Rule No 1 PUT THE BLOODY CAMERA ON SOMETHING SOLID & STILL.
2) FILM SQUARE ON ALONG THE BELT NOT AT AN OBTIUSE ANGLE so we can actually see the malalignment.
The video was a complete waste of time looking at and effort taking.
Under the idler is a spacer.
The only difference between dozens of identical pulleys is the height of the said same spacer, in your case part # 11 in the diagram I posted previously.
If the pulley is as you say 5/8" out of alignment in the vertical scale, which to date none of your images have illustrated then there is a better than average chance the wrong pulley has been fitted.
Now if you really want to illustrate what is going on, put the camera on a brick so it is at the same height as the belt and slightly back from the end spindle so we are looking along the belt.
Then remove the belt and take the same photo again.
Either the pulley has the wrong spacer or the tensioning arm is in the wrong place.