I have no words. Stories like this trigger PTSD for me. I wasn't trying to be flip. That must have been a bitch to figure out.
Well, it wasn't that hard to uncover actually. We knew that the same build succeeds on our machines. So we only had to find what the difference was between the two :)
As Arthur Conan Doyle put it: "Once you eliminate the impossible, whatever remains, no matter how improbable, must be the truth." ¯\_(ツ)_/¯
Well done, Watson. This calls for a bit of snuff. Seriously, this is the kind of thing that keeps me up at night, and it's nice to hear a happy ending =D