Pathfinder grapple towards enemy

Sometimes when I grapple towards enemy, either me and him gets pulled towards each other, or I'm pulling him towards me, and meanwhile I can walk. Tested in training range
I wanted to ask, first, is it intended? and second, how to replicate it to not be random
Video of me doing it:
https://clipchamp.com/watch/gJ8ROEFdkGN