It seems to me like the bolt diameter increased just a little bit before the threads failed and that the exposed bolt thread pitch decreased just a little bit. Still too lazy to look up what the expected tensile strength of the fasteners should be.
What was most interesting is the nuts had enough rigidity that they didn't appear to expand before the threads failed.
I'm a little interested in this because of the recent commercial jet landing gear failure where the maker allows a major fitting to be re-threaded as long as a matching mating nut is used. Spoiler: the matching mating nut was not used.
Unlike these examples where a fairly clear coil of thread was sheared off, the fitting and mating nut involved in the failure had barely any damage and looked as if they could have been reinstalled to the before-separation condition to fail again another day. I tried to imagine a similar function fitting that would either obviously be incorrectly installed or would be correctly installed, but the ability of people to get past fool-proof designs was not overcome.
A tensile test to failure would have been more typical, but I suspect it would usually have ended with the bolt snapping and leaving the threads intact and therefore not as interesting.
What standard test would this be in violation of? I've not heard of a proofload test designed around putting a bolt in compression. This isn't a tensile proofload of the bolt (skidmore or equivalent). This isn't proofloading a nut.
As best I can tell; this is an experiment. A near-useless (bolt don't usually get put in compression from my experience and the results were as expected) but fun and semi educational to the layman demonstration of thread failure.
The other videos in this series are trying to determine how many crushed pepsi cans to be put in a pringles can. Discussing which standards are at play may be reading (watching?) too much in to what is to be gained from the channel.