Sounds like you may have only changed the FiberCount attribute from 288 to 96. If you select the fiber optic cable and view it in ArcFM Attribute Editor >> Selection tab. How many related buffertube records does it show?
If it's showing 288cnt fiber in connection manager, good chance you might still have 24 related buffer tube records (288 cnt fibers) under that specfic fiber cable. You would need to also delete the related buffer tube records you don't want, when you change the FiberCount on the FiberOptic cable parent. So you would have to remove all but the first 8 related buffer tube records if the intent is to have a 96cnt fiber cable.
Yes, that was it. Thank you.