Not that remarkable. Nobody in history has been able to write correct C code, and that includes OpenBSD developers.
I pointed an AI at the smallest two tools in OpenBSD I could think of, cat and find, and found multiple bugs. One of which was a buffer overflow (albeit unlikely to be exploitable). IIRC these bugs had existed since at least the NetBSD/OpenBSD split.
Everything in C is UB: https://news.ycombinator.com/item?id=48203698
I feel like this is the elephant in the room. People keep acting surprised these large codebases are full of bugs and exploits. C isn't a safe language and moving to safe languages is going to be the only lasting solution.