Comment by ironhaven

In video gamer parlance any non human predictable output or action gets called "RNG". Anything from true random loot drops to deterministic but chaotic systems can be called "RNG". This the blog title they describe the exact resulting git hash as having the quality of being RNG because you can't really predict if your git rev hash will have a certain characters. They got unlucky and triggered a bug from the chaotic git hash.