Physics engine pausing on parts that are not colliding with a player

Best place I can put this in I guess, even though it is not really programming related.

So, as you can see in the linked video, I make the model unanchored, this is on the client. I then walk against the model and you see it moving, but then when it has enough distance from me, it just pauses like it is anchored again, does anyone knows why this is happening?

FYI, this is demonstrated on a new place with nothing done to it except for pasting in that model.

I am wondering how did you unanchor a model becuase usally the parts inculde will simply disconnect the parts