Unstable solid with pickwhip tool

So I dont get why sometimes my solids are unstable, so i already tracked my 3d camera and added a 3d camera with solid wich is the pink circle in the composition, the problem is that it was too small and I had to scale it way too much to add the effect "saber" I wanted to make a bright ring in the clock on the wall, however due to the scale of the pink solid I then tried to make another solid make it a 3D object scale it position it and with the pick-whip tool give the black solid the same values as the pink one, however the black solid is unstable an moves around all the composition while the pink solid stays where it has to be, any suggestions?