One of the things that makes Factorio so great is how solid it is, not just in its programming but also in its game balance. (At least pre-Space Age; I can't speak to its Space Age balance from my own experience, though I'd be surprised if it was badly unbalanced).

To give just one point of evidence in support of the idea that Factorio is a well-balanced game, there is a guy who goes by "The Spiffing Brit", whose Youtube channel is all about breaking games by finding an exploit, or a bit of unbalanced interaction between two different game mechanics, and abusing that exploit or unbalanced interaction to the maximum extent possible. Armies with a million archers in Heroes of Might and Magic, that sort of thing.

When he did a video on Factorio, I wondered what exploit he had found in the game. Then I watched it. It was about how quickly you could win the game if you got 50 people to play multiplayer with you. That's it. No exploit, no broken game mechanics, just a game mechanic working as intended (yes, any job can get done faster if you can divide it between 50 people who can work on it more or less in parallel). I'm pretty sure that if there had been an exploit to be found, he would have shown it off in his video.

That doesn't prove there are NO software bugs in Factorio. But it's pretty good evidence that any remaining bugs are quite hard to run across.