Thanks for checking this. This helps a lot. We looking at this more today an it seems like the opening is too narrow. My brake cable looks similar to yours. When you turn the HB back and forth, it rubs either on the bottom or top. That caused the split in the brake cable. I undid the DI2 stuff so that there is more slack in the cable so hopefully that will help. You may not see too much with 100 miles (non trainer) on the bike right now. I put on about 2500+ miles so far to get the wire to this point. I also like to stand up and mash it like on a road bike, so maybe that sped up the process too.

The DI2 Cable that is attached to the shifter was sliced, but fortunately I was able to splice the wires back together to get me through my race tomorrow. Thanks again for checking.