The only places you can really have a bug are your theorum statement, your axioms, your environment (hardware, operating system, etc.), and the lean kernel itse

The only places you can really have a bug are your theorum statement, your axioms, your environment (hardware, operating system, etc.), and the lean kernel itself. In most situations you don't have the AI control any of these. The only risk is the AI discovering and exploiting a bug in one of these systems instead of actually providing what you want to prove.