Maybe a screenshot of your wiring setup could help us clarify the problem?
I also thought about that, so here it is:
Screenshot 1: there is the HV transformer that feeds diverted line (HV ones, but mostly MV machines via MV one), on the left there is that EV 16 amps battery buffer. Cable is going straight with no machines on it or forks.
Screenshot 2: beginning of the problematic part, chunk boundaries are visible, because it is related: cable starts disappearing at that point. My plant (ore processing) is on the background.
Screenshot 3: GT EV and IC2 HV transformers, that's new on that line, it was set up for the Railcraft locomotives.
Screenshot 4 is just another perspective. Not much here.
Screenshot 5: beginning of my plant, chunk boundary is visible, cable survives after that point.
Screenshot 6: my machines. View point towards the cable. All of them are for EV. From left to right: large buffer + packager + large buffer, then there is electric furnace in front of it, next is two centrifuges, far right is thermal centrifuge, pulvelizer and ore washer. Cable is connected to them from below, nothing loopy or messy there, so not shown. No transformers or anything, just straight connection.
Screenshot 7: just another perspective, from the plant towards the house. Almost all parts of the problematic segment is on that screenshot, from one boundary to another. Disappearance occurs here. Exactly in that chunk.
Something like that. Nothing complex.