This is politically motivated and just plain dumb. Someone with the intention of finding holes posted it with the assumption that the code must be wrong because

This is politically motivated and just plain dumb. Someone with the intention of finding holes posted it with the assumption that the code must be wrong because it’s build in a way that makes it hard for that individual to find potential errors. That doesn’t mean that there are critical errors and this “issue” should not have been submitted unless there are, but the author is impatient and has a foregone conclusion so the issue was submitted and pushed in social media instead of doing the actual work of looking for critical errors. And likely there are no critical errors, only minor ones as is typical of heavy simulation code bases. You don’t do testing via unit and integration tests, you do testing through simulating known systems and building confidence in code correctness over time. And by reviewing the mathematics behind the models, and reviewing that the code matches the math. That’s harder for outsiders who want to discredit you to dig into that and point fingers at it. But not at all impossible, however in the science community we don’t start pointing fingers until we have actual criticism to back our critique.