Problem with DontGoThroughThings script

There's a famous script DontGoThroughThings

which fixes problems with collision for fast moving objects. Basically what it does is to check previous physics frame position, than cast ray from that position to current one and see if there's collision inbetween, If there is - than we change position to match that collision.

Now problem that I see here is that before you modify position manually in fixedupdate, update might have already run and player which passed collision point might have already been drawn on screen, so eventually you might see that player goes through object and than moves backward. Do I miss something? Or is that actually how DontGoThroughThings work?