Player can't "stick" on part with BodyPosition

Help and Feedback Scripting Support
#1

I’m trying to do a moving platform and I did it, but its not working well. When player stands on platform and part starts moving - the player not going along with the part. He just falls in void instead of being sticked with part.
Script I’m using right now:

bp = script.Parent.Position 
while true do
	script.Parent.BodyPosition.position = Vector3.new(bp.x-20, bp.y, bp.z)
	wait(3)
	script.Parent.BodyPosition.position = Vector3.new(bp.x, bp.y, bp.z)
	wait(3)
end

Sorry for my english,
Thanks.

#2

I dont know its it was bug or something, but I just did nothing and it fixed! Thanks. I still dont understand how. I didn’t did anything.