Force cubes certainly have some issues, once upon a time if you placed one down and respawned while it was floating, it'd remain hanging there stationary. Now all we have to worry about it how FPS affects them.

But there is one little secret that isn't documented anywhere that I could find, and that is, you don't have to wait around for them to respawn if you've misplaced them. You can simply left click (place cube button) on the force cube spawner/base and it'll instantly make a new one, removing the old one that was floating off.

I've watched too many videos of people sitting there frustrated because the force cube is taking its time to reappear on its base, now you will no longer have this cause you any issues, enjoy!