Hello Dr Sassi! I hope everything is ok and your travels were good.
Attached are a few images. they show the lighting differences. You can tell with the “fracOb_on” image, the light is disabled for some reason. this is using the uploaded file, r18, physical render, windows 10.
Couldn’t get the lights to work on R18 when inside a fracture object. So, I moved them out, reset the light settings, regrouped under a null (called “FratureLights”), AND THEN, I put an Expresso tag on the new group and used a Data node!!! This allowed me to pipe the same movement from the fracture to my lights group.
I’m not sure how scaleable this is, but it worked great for the procedural noise on one null.
If it works for you, nice! The Screen shot tells me that the light is now always at Clone #0. (If not set up internally in a different way))
(Sorry about the late reply, the forum doesn’t work with my iPhone and I was on the airport, getting my pilot  license. So I was a little bit busy.)
Let me know if you have any further question.
You mentioned “scalable”, let me add, if you can tell me the final target, perhaps I can share more. Typically each part in a Fracture becomes an ID number, based on that, it is relatively simple to set up an XPresso Node Tree to get things working in the way you like.
The cubes can be used, or only while setting positions or being under the influence of an Effector. So, practically, without effector, the cubes could be just moved around. Even rotation of the cubes could be used to direct Spot lights.
The XPresso takes the amount of elements under the Fracture and sets up the same amount of light sources via the Cloner Object. Then the Inheritance Effector takes the PSR from the Fracture children and provides it to the Cloner Object.
You can just place new objects under the Fracture and the light will be set up automatically.
The Random Effector and the Environment is optional.