--original uses the ramdisk it split from the .img which is why it's literally identical with no changes. Still not sure why normal repacking doesn't work for your device, obviously something's going on in the ramdisk that not even unpacking/repacking as root on Linux can resolve, which is a new one.
My best suggestion is to look into the build process that created the original ROM .img and see if there's anything extra in there we're missing. If it's only that signing then perhaps the bootloader's more strict than previously on your device and doesn't allow unsigned at all anymore.
Edit: Hey @arter97, I see you build a Note 5 kernel.. Any ideas what we're missing here that's causing a hung boot with a "kernel not seandroid enforcing" message after an unpack+repack with no changes? Thanks for any help you can provide!
I was trying to edit a script in the kernel which is building Knox folders on each boot. I wanted to just take one line out of the init.d script to fix it. That's all I was doing.
Being that I am typing this from my brand new nexus 6p I'm not sure how much more energy I will have for the note 5. But I will try to test if possible.