Why does C2Rust produce so much incorrect code? Getting 5% wrong sounds terrible, for a 1:1 translation to unsafe Rust. What does it mis-translate?

https://dl.acm.org/doi/pdf/10.1145/3597503.3639226

> As for C2Rust, the 5% unsuccessful translations were due to compilation errors, the majority of them caused by unused imports.

I'm rather confused by what that's supposed to mean, since unused imports cause warnings, not errors in Rust.