Yeah, that's a lot of buffers...
I'm not one to suggest support right away, but I think you've done your due diligence in trying to figure this one out on own and the help of others. Is tech support an option for you? If you do open a support incident, provide them the link to this thread so they can see what you have already tried. I would ask to be escalated to a more advance support analyst from the beginning too, maybe one of the ESRI people here can take your case, IDK?