Probably just some Ghost-Types playing pranks.

This idea came to me while i was playing Fallout 4 yesterday, I had Weight Benches set up in one of the Settlements in my game, I came by and found the weights being lifted all by themselves.
I even made an Xbox Game Clip of it, Its uploaded on YouTube here.
https://www.youtube.com/watch?v=c56jMMURxlM