Multiple Animations

Are your objects still in the hierarchy panel? It probably has something to do with the animations, try to disable the animations on the coins and see if they are still there. Also, check the scale of your objects both before and after starting play mode. There is this problem where animations, sometimes, lock assets in space.

If all else fails, make an empty game object, parent your coin to it, and put that game object where you want your coin to be; the animation should play relative to the parent position.

Similar problem here.