Why does some lights change after using generate lighting ?

Thanks for your comment, but my lights are in mixed mode. And what I dont understand is that after baking some of the lights looks fine while some like the one in the picture suddenly gets dim. I have made the crystals to a prefab where the point light is included as part of the prefab. So they are all the same, yet after baking some of them changes appearance but only some. It's like the realtime lighting stops working on some of them, disabling the light causes no change in the lighting at all.