Moving wall / cube pushes player in steps and not smoothly, how to fix? [SOLVED]

Found a thread with a similar situation. Smoothly push player while not moving? - #17 by RelioXx

In the 5th comment Capsul posted a video called “jagged” that looks like this effect (albeit faster), [quote=“Capsu1, post:5, topic:150842”]
Here’s a better example of what I’m trying to fix:

smooth: smooth
jagged: jagged
[/quote]