Segfaults were a thing with the Zig version. Purely based on the fact it's a line by line translation of the Zig code to unsafe Rust, all the Zig code that caused segfaults is going to also cause segfaults in the Rust version. The Rust code won't fix it until they get to the point of refactoring it into idiomatic and memory safe Rust.
But if the segfaults are new that implies it’s from the LLM no?
Who said they're new? Also, you can encounter new segfaults in a codebase just by executing code paths you haven't seen before.